diff --git a/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/comparator_profiler.h b/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/comparator_profiler.h
index fc95d4bf1b1..4395c25a54b 100644
--- a/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/comparator_profiler.h
+++ b/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/comparator_profiler.h
@@ -19,6 +19,7 @@
 
 
 #include <CGAL/Apollonius_graph_2/basic.h>
+#include <atomic>
 
 namespace CGAL {
 
@@ -32,8 +33,8 @@ public:
   typedef bool bool_;
   typedef unsigned long long_;
 #else
-  typedef CGAL::cpp11::atomic<bool> bool_;
-  typedef CGAL::cpp11::atomic<unsigned long> long_;
+  typedef std::atomic<bool> bool_;
+  typedef std::atomic<unsigned long> long_;
 #endif
 
   static bool_ count_cases;
diff --git a/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/predicate_profiler.h b/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/predicate_profiler.h
index b2b7b93e33d..cf78798b185 100644
--- a/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/predicate_profiler.h
+++ b/Apollonius_graph_2/include/CGAL/Apollonius_graph_2/predicate_profiler.h
@@ -19,6 +19,7 @@
 
 
 #include <CGAL/Apollonius_graph_2/basic.h>
+#include <atomic>
 
 #define AG2_PROFILE_PREDICATES
 
@@ -32,7 +33,7 @@ public:
 #ifdef CGAL_NO_ATOMIC
   typedef unsigned long long_;
 #else
-  typedef CGAL::cpp11::atomic<unsigned long> long_;
+  typedef std::atomic<unsigned long> long_;
 #endif
 
   // high level predicates
diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_circle_segment_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_circle_segment_traits_2.h
index 8155e8b2cdd..dfa5bf667d0 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_circle_segment_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_circle_segment_traits_2.h
@@ -28,6 +28,7 @@
 #include <CGAL/Arr_geometry_traits/Circle_segment_2.h>
 
 #include <fstream>
+#include <atomic>
 
 namespace CGAL {
 
@@ -79,7 +80,7 @@ public:
 #ifdef CGAL_NO_ATOMIC
     static unsigned int index;
 #else
-    static CGAL::cpp11::atomic<unsigned int> index;
+    static std::atomic<unsigned int> index;
 #endif
     return (++index);
   }
diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_conic_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_conic_traits_2.h
index 89b758557db..079ba7d1d04 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_conic_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_conic_traits_2.h
@@ -23,6 +23,7 @@
  */
 
 #include <fstream>
+#include <atomic>
 
 #include <CGAL/tags.h>
 #include <CGAL/Arr_tags.h>
@@ -107,7 +108,7 @@ public:
 #ifdef CGAL_NO_ATOMIC
     static unsigned int index;
 #else
-    static CGAL::cpp11::atomic<unsigned int> index;
+    static std::atomic<unsigned int> index;
 #endif
     return (++index);
   }
diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_counting_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_counting_traits_2.h
index 642ba527cd5..2a745798ec4 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_counting_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_counting_traits_2.h
@@ -26,6 +26,7 @@
 
 #include <iostream>
 #include <string.h>
+#include <atomic>
 
 #include <CGAL/basic.h>
 #include <CGAL/Arr_enums.h>
@@ -949,7 +950,7 @@ public:
 #ifdef CGAL_NO_ATOMIC
     static unsigned int counter;
 #else
-    static CGAL::cpp11::atomic<unsigned int> counter;
+    static std::atomic<size_t> counter;
 #endif
     if (doit) ++counter;
     return counter;
diff --git a/Box_intersection_d/include/CGAL/Box_intersection_d/Box_d.h b/Box_intersection_d/include/CGAL/Box_intersection_d/Box_d.h
index 7b0b74f5679..ddadb14852e 100644
--- a/Box_intersection_d/include/CGAL/Box_intersection_d/Box_d.h
+++ b/Box_intersection_d/include/CGAL/Box_intersection_d/Box_d.h
@@ -24,6 +24,7 @@
 
 #include <algorithm>
 #include <array>
+#include <atomic>
 
 namespace CGAL {
 
@@ -37,7 +38,7 @@ struct Unique_numbers {
 #ifdef CGAL_NO_ATOMIC
       static std::size_t n = 0;
 #else
-      static CGAL::cpp11::atomic<std::size_t> n; // initialized to 0
+      static std::atomic<std::size_t> n; // initialized to 0
 #endif
       i = n++;
     }
diff --git a/CGAL_Core/include/CGAL/CORE/CoreDefs.h b/CGAL_Core/include/CGAL/CORE/CoreDefs.h
index 22cde3a4a31..57c3da34645 100644
--- a/CGAL_Core/include/CGAL/CORE/CoreDefs.h
+++ b/CGAL_Core/include/CGAL/CORE/CoreDefs.h
@@ -31,6 +31,8 @@
 #include <CGAL/CORE/extLong.h>
 #include <CGAL/disable_warnings.h>
 
+#include <atomic>
+
 #ifdef CGAL_HEADER_ONLY
 
   #define CGAL_GLOBAL_STATE_VAR(TYPE, NAME, VALUE)  \
@@ -74,7 +76,7 @@ namespace CORE {
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(bool, AbortFlag, true)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, AbortFlag, true)
+CGAL_GLOBAL_STATE_VAR(std::atomic<bool>, AbortFlag, true)
 #endif
 
 /// Invalid Flag -- initiallly value is non-negative
@@ -85,7 +87,7 @@ CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, AbortFlag, true)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(int, InvalidFlag, 0)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<int>, InvalidFlag, 0)
+CGAL_GLOBAL_STATE_VAR(std::atomic<int>, InvalidFlag, 0)
 #endif
 
 /// Escape Precision in bits
@@ -101,7 +103,7 @@ CGAL_GLOBAL_STATE_VAR(long, EscapePrecFlag, 0)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(bool, EscapePrecWarning, true)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, EscapePrecWarning, true)
+CGAL_GLOBAL_STATE_VAR(std::atomic<bool>, EscapePrecWarning, true)
 #endif
 
 // These following two values determine the precision of computing
@@ -123,7 +125,7 @@ CGAL_GLOBAL_STATE_VAR(extLong, defAbsPrec, CORE_posInfty)
 #ifdef CGAL_NO_ATOMIC
     CGAL_GLOBAL_STATE_VAR(long, defBigFloatOutputDigits, 10)
 #else
-    CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<long>, defBigFloatOutputDigits, 10)
+    CGAL_GLOBAL_STATE_VAR(std::atomic<long>, defBigFloatOutputDigits, 10)
 #endif
 
 /// default input precision in digits for converting a string to a Real or Expr
@@ -137,7 +139,7 @@ CGAL_GLOBAL_STATE_VAR(extLong, defInputDigits, CORE_posInfty)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(long, defOutputDigits, 10) // == get_static_defBigFloatOutputDigits()
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<long>, defOutputDigits, 10) // == get_static_defBigFloatOutputDigits()
+CGAL_GLOBAL_STATE_VAR(std::atomic<long>, defOutputDigits, 10) // == get_static_defBigFloatOutputDigits()
 #endif
 
 /// default input precision in digits for converting a string to a BigFloat
@@ -145,7 +147,7 @@ CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<long>, defOutputDigits, 10) // == get_
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(long, defBigFloatInputDigits, 16)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<long>, defBigFloatInputDigits, 16)
+CGAL_GLOBAL_STATE_VAR(std::atomic<long>, defBigFloatInputDigits, 16)
 #endif
 
 inline
@@ -168,7 +170,7 @@ CGAL_GLOBAL_STATE_VAR(extLong, defBFsqrtAbsPrec, 54)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(bool, fpFilterFlag, true)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, fpFilterFlag, true)
+CGAL_GLOBAL_STATE_VAR(std::atomic<bool>, fpFilterFlag, true)
 #endif
 
 
@@ -176,7 +178,7 @@ CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, fpFilterFlag, true)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(bool, incrementalEvalFlag, true)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, incrementalEvalFlag, true)
+CGAL_GLOBAL_STATE_VAR(std::atomic<bool>, incrementalEvalFlag, true)
 #endif
 
 
@@ -184,7 +186,7 @@ CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, incrementalEvalFlag, true)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(bool, progressiveEvalFlag, true)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, progressiveEvalFlag, true)
+CGAL_GLOBAL_STATE_VAR(std::atomic<bool>, progressiveEvalFlag, true)
 #endif
 
 
@@ -192,14 +194,14 @@ CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, progressiveEvalFlag, true)
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(bool, rationalReduceFlag, false)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<bool>, rationalReduceFlag, false)
+CGAL_GLOBAL_STATE_VAR(std::atomic<bool>, rationalReduceFlag, false)
 #endif
 
 /// default initial (bit) precision for AddSub Progressive Evaluation
 #ifdef CGAL_NO_ATOMIC
 CGAL_GLOBAL_STATE_VAR(long, defInitialProgressivePrec, 64)
 #else
-CGAL_GLOBAL_STATE_VAR(CGAL::cpp11::atomic<long>, defInitialProgressivePrec, 64)
+CGAL_GLOBAL_STATE_VAR(std::atomic<long>, defInitialProgressivePrec, 64)
 #endif
 
 //////////////////////////////////////////////////////////////
diff --git a/CGAL_Core/include/CGAL/CORE/CoreDefs_impl.h b/CGAL_Core/include/CGAL/CORE/CoreDefs_impl.h
index b7436178b0a..d28326496f3 100644
--- a/CGAL_Core/include/CGAL/CORE/CoreDefs_impl.h
+++ b/CGAL_Core/include/CGAL/CORE/CoreDefs_impl.h
@@ -24,6 +24,8 @@
 
 #include "CGAL/CORE/CoreDefs.h"
 
+#include <atomic>
+
 namespace CORE {
 
 //  Default Values
@@ -50,7 +52,7 @@ int IOErrorFlag = 0;
 #ifdef CGAL_NO_ATOMIC
 bool AbortFlag = true;
 #else
-CGAL::cpp11::atomic<bool> AbortFlag(true);
+std::atomic<bool> AbortFlag(true);
 #endif
 
 /**
@@ -61,7 +63,7 @@ CGAL::cpp11::atomic<bool> AbortFlag(true);
 #ifdef CGAL_NO_ATOMIC
 int InvalidFlag = 0;
 #else
-CGAL::cpp11::atomic<int> InvalidFlag(0);
+std::atomic<int> InvalidFlag(0);
 #endif
 
 /* ************************************************************
@@ -97,7 +99,7 @@ long EscapePrecFlag = 0;
 #ifdef CGAL_NO_ATOMIC
 bool EscapePrecWarning = true;
 #else
-CGAL::cpp11::atomic<bool> EscapePrecWarning(true);
+std::atomic<bool> EscapePrecWarning(true);
 #endif
 
 /** The Composite Precision [defAbsPrec, defRelPrec]
@@ -117,7 +119,7 @@ extLong defRelPrec = 60;
 #ifdef CGAL_NO_ATOMIC
 long defBigFloatOutputDigits = 10;
 #else
-CGAL::cpp11::atomic<long> defBigFloatOutputDigits(10);
+std::atomic<long> defBigFloatOutputDigits(10);
 #endif
 
 /**  NORMALLY, we like to make this equal to defBigFloatOutputDigits
@@ -125,7 +127,7 @@ CGAL::cpp11::atomic<long> defBigFloatOutputDigits(10);
 #ifdef CGAL_NO_ATOMIC
 long defOutputDigits = 10;
 #else
-CGAL::cpp11::atomic<long> defOutputDigits(10); // == defBigFloatOutputDigits;
+std::atomic<long> defOutputDigits(10); // == defBigFloatOutputDigits;
 #endif
 
 /** String Input Precision */
@@ -142,7 +144,7 @@ extLong defInputDigits = CORE_posInfty;
 #ifdef CGAL_NO_ATOMIC
 long defBigFloatInputDigits = 16;
 #else
-CGAL::cpp11::atomic<long> defBigFloatInputDigits(16);
+std::atomic<long> defBigFloatInputDigits(16);
 #endif
 
 /* ************************************************************
@@ -154,7 +156,7 @@ CGAL::cpp11::atomic<long> defBigFloatInputDigits(16);
 #ifdef CGAL_NO_ATOMIC
 bool fpFilterFlag = true;
 #else
-CGAL::cpp11::atomic<bool> fpFilterFlag(true);
+std::atomic<bool> fpFilterFlag(true);
 #endif
 
 /** IncrementaL evaluation flag
@@ -163,7 +165,7 @@ CGAL::cpp11::atomic<bool> fpFilterFlag(true);
 #ifdef CGAL_NO_ATOMIC
 bool incrementalEvalFlag = true;
 #else
-CGAL::cpp11::atomic<bool> incrementalEvalFlag(true);
+std::atomic<bool> incrementalEvalFlag(true);
 #endif
 
 /** Progressive evaluation flag
@@ -171,7 +173,7 @@ CGAL::cpp11::atomic<bool> incrementalEvalFlag(true);
 #ifdef CGAL_NO_ATOMIC
 bool progressiveEvalFlag = true;
 #else
-CGAL::cpp11::atomic<bool> progressiveEvalFlag(true);
+std::atomic<bool> progressiveEvalFlag(true);
 #endif
 
 /** Initial progressive evaluation precision
@@ -179,7 +181,7 @@ CGAL::cpp11::atomic<bool> progressiveEvalFlag(true);
 #ifdef CGAL_NO_ATOMIC
 long defInitialProgressivePrec = 64;
 #else
-CGAL::cpp11::atomic<long> defInitialProgressivePrec(64);
+std::atomic<long> defInitialProgressivePrec(64);
 #endif
 
 /** RATIONAL REDUCTION FLAG
@@ -187,7 +189,7 @@ CGAL::cpp11::atomic<long> defInitialProgressivePrec(64);
 #ifdef CGAL_NO_ATOMIC
 bool rationalReduceFlag = false;
 #else
-CGAL::cpp11::atomic<bool> rationalReduceFlag(false);
+std::atomic<bool> rationalReduceFlag(false);
 #endif
 #endif // CGAL_HEADER_ONLY
 
diff --git a/Mesh_3/include/CGAL/Mesh_3/Mesher_3.h b/Mesh_3/include/CGAL/Mesh_3/Mesher_3.h
index 718a730032d..1b50447e088 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Mesher_3.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Mesher_3.h
@@ -55,6 +55,7 @@
 #include <boost/format.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 #include <string>
+#include <atomic>
 
 namespace CGAL {
 namespace Mesh_3 {
@@ -212,7 +213,7 @@ public:
            std::size_t maximal_number_of_vertices = 0,
            Mesh_error_code* error_code = 0
 #ifndef CGAL_NO_ATOMIC
-           , CGAL::cpp11::atomic<bool>* stop_ptr = 0
+           , std::atomic<bool>* stop_ptr = 0
 #endif
            );
 
@@ -284,7 +285,7 @@ private:
 
 #ifndef CGAL_NO_ATOMIC
   /// Pointer to the atomic Boolean that can stop the process
-  CGAL::cpp11::atomic<bool>* const stop_ptr;
+  std::atomic<bool>* const stop_ptr;
 #endif
 
 #ifdef CGAL_LINKED_WITH_TBB
@@ -343,7 +344,7 @@ Mesher_3<C3T3,MC,MD>::Mesher_3(C3T3& c3t3,
                                std::size_t maximal_number_of_vertices,
                                Mesh_error_code* error_code
 #ifndef CGAL_NO_ATOMIC
-                               , CGAL::cpp11::atomic<bool>* stop_ptr
+                               , std::atomic<bool>* stop_ptr
 #endif
                                )
 : Base(c3t3.bbox(),
diff --git a/Mesh_3/include/CGAL/Mesh_3/Mesher_level.h b/Mesh_3/include/CGAL/Mesh_3/Mesher_level.h
index 2da097ef8a5..77b1836df6a 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Mesher_level.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Mesher_level.h
@@ -36,7 +36,7 @@
 # include <tbb/task.h>
 #endif
 
-#include <string>
+#include <atomic>
 
 namespace CGAL { namespace Mesh_3 {
 
@@ -676,7 +676,7 @@ public:
   void set_lock_ds(Lock_data_structure *) {}
   void set_worksharing_ds(WorksharingDataStructureType *) {}
 #ifndef CGAL_NO_ATOMIC
-  void set_stop_pointer(CGAL::cpp11::atomic<bool>*) {}
+  void set_stop_pointer(std::atomic<bool>*) {}
 #endif
 
 protected:
@@ -1148,7 +1148,7 @@ public:
   }
 
 #ifndef CGAL_NO_ATOMIC
-  void set_stop_pointer(CGAL::cpp11::atomic<bool>* stop_ptr)
+  void set_stop_pointer(std::atomic<bool>* stop_ptr)
   {
     m_stop_ptr = stop_ptr;
   }
@@ -1178,7 +1178,7 @@ protected:
 
   tbb::task *m_empty_root_task;
 #ifndef CGAL_NO_ATOMIC
-  CGAL::cpp11::atomic<bool>* m_stop_ptr;
+  std::atomic<bool>* m_stop_ptr;
 #endif
 
 private:
diff --git a/Mesh_3/include/CGAL/Mesh_3/Protect_edges_sizing_field.h b/Mesh_3/include/CGAL/Mesh_3/Protect_edges_sizing_field.h
index 0a5826774bd..fb0da075047 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Protect_edges_sizing_field.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Protect_edges_sizing_field.h
@@ -70,6 +70,7 @@
 #include <string>
 #include <utility>
 #include <vector>
+#include <atomic>
 
 namespace CGAL {
 namespace Mesh_3 {
@@ -143,7 +144,7 @@ public:
                              std::size_t maximal_number_of_vertices = 0,
                              Mesh_error_code* error_code = 0
 #ifndef CGAL_NO_ATOMIC
-                             , CGAL::cpp11::atomic<bool>* stop_ptr = 0
+                             , std::atomic<bool>* stop_ptr = 0
 #endif
                              );
 
@@ -469,7 +470,7 @@ private:
   Mesh_error_code* const error_code_;
 #ifndef CGAL_NO_ATOMIC
   /// Pointer to the atomic Boolean that can stop the process
-  CGAL::cpp11::atomic<bool>* const stop_ptr_;
+  std::atomic<bool>* const stop_ptr_;
 #endif
 };
 
@@ -481,7 +482,7 @@ Protect_edges_sizing_field(C3T3& c3t3, const MD& domain,
                            std::size_t maximal_number_of_vertices,
                            Mesh_error_code* error_code
 #ifndef CGAL_NO_ATOMIC
-                           , CGAL::cpp11::atomic<bool>* stop_ptr
+                           , std::atomic<bool>* stop_ptr
 #endif
                            )
   : c3t3_(c3t3)
diff --git a/Mesh_3/include/CGAL/Mesh_3/Refine_cells_3.h b/Mesh_3/include/CGAL/Mesh_3/Refine_cells_3.h
index 30726de2fcc..6a234a15311 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Refine_cells_3.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Refine_cells_3.h
@@ -40,7 +40,7 @@
 #include <boost/mpl/if.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 #include <sstream>
-
+#include <atomic>
 
 namespace CGAL {
 
@@ -318,7 +318,7 @@ public:
                  C3T3& c3t3,
                  std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                , CGAL::cpp11::atomic<bool>* stop_ptr
+                , std::atomic<bool>* stop_ptr
 #endif
                 );
   // For parallel
@@ -331,7 +331,7 @@ public:
                  WorksharingDataStructureType *worksharing_ds,
                  std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                , CGAL::cpp11::atomic<bool>* stop_ptr
+                , std::atomic<bool>* stop_ptr
 #endif
                 );
 
@@ -572,7 +572,7 @@ private:
 
 #ifndef CGAL_NO_ATOMIC
   /// Pointer to the atomic Boolean that can stop the process
-  CGAL::cpp11::atomic<bool>* const m_stop_ptr;
+  std::atomic<bool>* const m_stop_ptr;
 #endif
 private:
   // Disabled copy constructor
@@ -594,7 +594,7 @@ Refine_cells_3(Tr& triangulation,
                C3T3& c3t3,
                std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-               , CGAL::cpp11::atomic<bool>* stop_ptr
+               , std::atomic<bool>* stop_ptr
 #endif
                )
   : Mesher_level<Tr, Self, Cell_handle, P_,
@@ -627,7 +627,7 @@ Refine_cells_3(Tr& triangulation,
                WorksharingDataStructureType *worksharing_ds,
                std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-               , CGAL::cpp11::atomic<bool>* stop_ptr
+               , std::atomic<bool>* stop_ptr
 #endif
                )
   : Mesher_level<Tr, Self, Cell_handle, P_,
diff --git a/Mesh_3/include/CGAL/Mesh_3/Refine_facets_3.h b/Mesh_3/include/CGAL/Mesh_3/Refine_facets_3.h
index fe720c2399d..f90ecc9273b 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Refine_facets_3.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Refine_facets_3.h
@@ -50,6 +50,7 @@
 #include <CGAL/tuple.h>
 #include <boost/type_traits/is_convertible.hpp>
 #include <sstream>
+#include <atomic>
 
 namespace CGAL {
 
@@ -254,7 +255,7 @@ public:
                        const Criteria& criteria,
                        std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                       , CGAL::cpp11::atomic<bool>* stop_ptr
+                       , std::atomic<bool>* stop_ptr
 #endif
                        )
     : r_tr_(tr)
@@ -608,7 +609,7 @@ protected:
   std::size_t m_maximal_number_of_vertices_;
 #ifndef CGAL_NO_ATOMIC
   /// Pointer to the atomic Boolean that can stop the process
-  CGAL::cpp11::atomic<bool>* const m_stop_ptr;
+  std::atomic<bool>* const m_stop_ptr;
 #endif
 }; // end class template Refine_facets_3_base
 
@@ -776,7 +777,7 @@ public:
                   int mesh_topology,
                   std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                  , CGAL::cpp11::atomic<bool>* stop_ptr
+                  , std::atomic<bool>* stop_ptr
 #endif
                   );
   // For parallel
@@ -789,7 +790,7 @@ public:
                   WorksharingDataStructureType *worksharing_ds,
                   std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                  , CGAL::cpp11::atomic<bool>* stop_ptr
+                  , std::atomic<bool>* stop_ptr
 #endif
                   );
 
@@ -909,7 +910,7 @@ Refine_facets_3(Tr& triangulation,
                 int mesh_topology,
                 std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                , CGAL::cpp11::atomic<bool>* stop_ptr
+                , std::atomic<bool>* stop_ptr
 #endif
                 )
   : Rf_base(triangulation, c3t3, oracle, criteria, mesh_topology,
@@ -938,7 +939,7 @@ Refine_facets_3(Tr& triangulation,
                 WorksharingDataStructureType *worksharing_ds,
                 std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                , CGAL::cpp11::atomic<bool>* stop_ptr
+                , std::atomic<bool>* stop_ptr
 #endif
                 )
   : Rf_base(triangulation, c3t3, oracle, criteria, maximal_number_of_vertices
diff --git a/Mesh_3/include/CGAL/Mesh_3/Refine_facets_manifold_base.h b/Mesh_3/include/CGAL/Mesh_3/Refine_facets_manifold_base.h
index aa6a83b9e0e..e68892bd600 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Refine_facets_manifold_base.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Refine_facets_manifold_base.h
@@ -30,6 +30,7 @@
 
 #include <set>
 #include <vector>
+#include <atomic>
 
 namespace CGAL {
 
@@ -307,7 +308,7 @@ public:
                               int mesh_topology,
                               std::size_t maximal_number_of_vertices
 #ifndef CGAL_NO_ATOMIC
-                              , CGAL::cpp11::atomic<bool>* stop_ptr
+                              , std::atomic<bool>* stop_ptr
 #endif
                               )
     : Base(triangulation,
diff --git a/Mesh_3/include/CGAL/make_mesh_3.h b/Mesh_3/include/CGAL/make_mesh_3.h
index 6bc7be6c596..a75e120da69 100644
--- a/Mesh_3/include/CGAL/make_mesh_3.h
+++ b/Mesh_3/include/CGAL/make_mesh_3.h
@@ -32,6 +32,8 @@
 #include <boost/mpl/has_xxx.hpp>
 #include <boost/parameter/preprocessor.hpp>
 
+#include <atomic>
+
 namespace CGAL {
 
 namespace parameters {
@@ -192,7 +194,7 @@ void init_c3t3_with_features(C3T3& c3t3,
                              std::size_t maximal_number_of_vertices = 0,
                              Mesh_error_code* pointer_to_error_code = 0
 #ifndef CGAL_NO_ATOMIC
-                             , CGAL::cpp11::atomic<bool>* pointer_to_stop = 0
+                             , std::atomic<bool>* pointer_to_stop = 0
 #endif
                              )
 {
diff --git a/Mesh_3/include/CGAL/refine_mesh_3.h b/Mesh_3/include/CGAL/refine_mesh_3.h
index 4846b12c97e..acbf847b26b 100644
--- a/Mesh_3/include/CGAL/refine_mesh_3.h
+++ b/Mesh_3/include/CGAL/refine_mesh_3.h
@@ -31,6 +31,8 @@
 
 #include <boost/parameter/preprocessor.hpp>
 
+#include <atomic>
+
 namespace CGAL {
 
 namespace details {
@@ -195,7 +197,7 @@ struct Manifold_options {
 // Various Mesh_3 option
 struct Mesh_3_options {
 #ifndef CGAL_NO_ATOMIC
-      typedef CGAL::cpp11::atomic<bool>* Pointer_to_stop_atomic_boolean_t;
+      typedef std::atomic<bool>* Pointer_to_stop_atomic_boolean_t;
 #else
       typedef bool* Pointer_to_stop_atomic_boolean_t;
 #endif
diff --git a/Nef_3/include/CGAL/Nef_3/SNC_indexed_items.h b/Nef_3/include/CGAL/Nef_3/SNC_indexed_items.h
index 7194fbae8ca..82740860553 100644
--- a/Nef_3/include/CGAL/Nef_3/SNC_indexed_items.h
+++ b/Nef_3/include/CGAL/Nef_3/SNC_indexed_items.h
@@ -23,6 +23,8 @@
 #include <CGAL/Nef_3/SHalfloop.h>
 #include <CGAL/Nef_3/SFace.h>
 
+#include <atomic>
+
 #undef CGAL_NEF_DEBUG
 #define CGAL_NEF_DEBUG 83
 #include <CGAL/Nef_2/debug.h>
@@ -39,7 +41,7 @@ class Index_generator {
 #ifdef CGAL_NO_ATOMIC
     static int unique;
 #else
-    static CGAL::cpp11::atomic<int> unique;
+    static std::atomic<int> unique;
 #endif
     return unique++;
   }
diff --git a/Number_types/include/CGAL/Counted_number.h b/Number_types/include/CGAL/Counted_number.h
index 02b3a1d111c..502a0e1d2a3 100644
--- a/Number_types/include/CGAL/Counted_number.h
+++ b/Number_types/include/CGAL/Counted_number.h
@@ -21,6 +21,7 @@
 #include <CGAL/number_type_basic.h>
 #include <CGAL/boost/iterator/transform_iterator.hpp> // for Root_of_selector
 #include <iostream>
+#include <atomic>
 
 namespace CGAL {
 
@@ -29,7 +30,7 @@ class Counted_number {
 #ifdef CGAL_NO_ATOMIC
     static unsigned long
 #else
-    static CGAL::cpp11::atomic<unsigned long>
+    static std::atomic<unsigned long>
 #endif
                          s_neg_count, s_add_count, s_sub_count,
                          s_mul_count, s_div_count,
@@ -279,64 +280,64 @@ template< class NT >
 unsigned long Counted_number<NT>::s_mod_count = 0;
 #else
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_neg_count;
+std::atomic<unsigned long> Counted_number<NT>::s_neg_count;
 
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_add_count;
+std::atomic<unsigned long> Counted_number<NT>::s_add_count;
 
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_sub_count;
+std::atomic<unsigned long> Counted_number<NT>::s_sub_count;
 
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_mul_count;
+std::atomic<unsigned long> Counted_number<NT>::s_mul_count;
 
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_div_count;
+std::atomic<unsigned long> Counted_number<NT>::s_div_count;
 
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_eq_count;
+std::atomic<unsigned long> Counted_number<NT>::s_eq_count;
 
 template <class NT>
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_comp_count;
+std::atomic<unsigned long> Counted_number<NT>::s_comp_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_simplify_count;
+std::atomic<unsigned long> Counted_number<NT>::s_simplify_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_unit_part_count;
+std::atomic<unsigned long> Counted_number<NT>::s_unit_part_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_is_zero_count;
+std::atomic<unsigned long> Counted_number<NT>::s_is_zero_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_is_one_count;
+std::atomic<unsigned long> Counted_number<NT>::s_is_one_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_square_count;
+std::atomic<unsigned long> Counted_number<NT>::s_square_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_integral_division_count;
+std::atomic<unsigned long> Counted_number<NT>::s_integral_division_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_is_square_count;
+std::atomic<unsigned long> Counted_number<NT>::s_is_square_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_sqrt_count;
+std::atomic<unsigned long> Counted_number<NT>::s_sqrt_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_kth_root_count;
+std::atomic<unsigned long> Counted_number<NT>::s_kth_root_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_root_of_count;
+std::atomic<unsigned long> Counted_number<NT>::s_root_of_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_gcd_count;
+std::atomic<unsigned long> Counted_number<NT>::s_gcd_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_div_mod_count;
+std::atomic<unsigned long> Counted_number<NT>::s_div_mod_count;
 
 template< class NT >
-CGAL::cpp11::atomic<unsigned long> Counted_number<NT>::s_mod_count;
+std::atomic<unsigned long> Counted_number<NT>::s_mod_count;
 #endif
 
 
diff --git a/Polyhedron/demo/Polyhedron/include/run_with_qprogressdialog.h b/Polyhedron/demo/Polyhedron/include/run_with_qprogressdialog.h
index 932530e76ba..42345fb335a 100644
--- a/Polyhedron/demo/Polyhedron/include/run_with_qprogressdialog.h
+++ b/Polyhedron/demo/Polyhedron/include/run_with_qprogressdialog.h
@@ -6,6 +6,8 @@
 
 #include "Callback_signaler.h"
 
+#include <atomic>
+
 typedef CGAL::Parallel_if_available_tag Concurrency_tag;
 
 class Signal_callback
@@ -111,7 +113,7 @@ void run_with_qprogressdialog (Functor& functor,
 #ifdef CGAL_HAS_STD_THREADS
   if (boost::is_convertible<ConcurrencyTag, CGAL::Parallel_tag>::value)
   {
-    CGAL::cpp11::thread thread (functor);
+    std::thread thread (functor);
 
     while (*signal_callback->latest_adv != 1. &&
            *signal_callback->state)