diff --git a/Visibility_2/include/CGAL/Rotational_sweep_visibility_2.h b/Visibility_2/include/CGAL/Rotational_sweep_visibility_2.h
index 46b34a44b85..46048b92078 100644
--- a/Visibility_2/include/CGAL/Rotational_sweep_visibility_2.h
+++ b/Visibility_2/include/CGAL/Rotational_sweep_visibility_2.h
@@ -26,6 +26,7 @@
 #include <CGAL/Arrangement_2.h>
 #include <CGAL/bounding_box.h>
 #include <CGAL/assertions.h>
+#include <CGAL/Kernel/global_functions_2.h>
 #include <boost/unordered_map.hpp> 
 #include <iterator>
 
diff --git a/Visibility_2/include/CGAL/Simple_polygon_visibility_2.h b/Visibility_2/include/CGAL/Simple_polygon_visibility_2.h
index 61c8de1efbb..d7a9e5d76c4 100644
--- a/Visibility_2/include/CGAL/Simple_polygon_visibility_2.h
+++ b/Visibility_2/include/CGAL/Simple_polygon_visibility_2.h
@@ -27,6 +27,7 @@
 #include <CGAL/enum.h>
 #include <CGAL/Visibility_2/visibility_utils.h>
 #include <CGAL/Arrangement_2.h>
+#include <CGAL/Kernel/global_functions_2.h>
 #include <CGAL/Arr_walk_along_line_point_location.h>
 #include <CGAL/assertions.h>
 #include <stack>
diff --git a/Visibility_2/include/CGAL/Visibility_2/visibility_utils.h b/Visibility_2/include/CGAL/Visibility_2/visibility_utils.h
index e787cc551b2..5e332a73a3c 100644
--- a/Visibility_2/include/CGAL/Visibility_2/visibility_utils.h
+++ b/Visibility_2/include/CGAL/Visibility_2/visibility_utils.h
@@ -22,6 +22,7 @@
 #ifndef CGAL_VISIBILITY_UTILS_H
 #define CGAL_VISIBILITY_UTILS_H
 
+#include <iostream>
 #include <vector>
 #include <CGAL/tags.h>
 #include <CGAL/enum.h>