diff --git a/ReadMe.md b/ReadMe.md
index 0647f42..02b02c0 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -11,7 +11,7 @@ int main()
 {
     AStar::Generator generator;
     // Set 2d map size.
-    generator.setWorldSize({25, 25});
+    generator.setWorldSize({25, 25}); // World is between {0, 0} and {24, 24}
     // You can use a few heuristics : manhattan, euclidean or octagonal.
     generator.setHeuristic(AStar::Heuristic::euclidean);
     generator.setDiagonalMovement(true);
diff --git a/source/AStar.cpp b/source/AStar.cpp
index 7bf471a..4205570 100644
--- a/source/AStar.cpp
+++ b/source/AStar.cpp
@@ -25,7 +25,7 @@ AStar::uint AStar::Node::getScore()
     return G + H;
 }
 
-AStar::Generator::Generator()
+AStar::Generator::Generator() noexcept : heuristic{}, direction{}, walls{}, worldSize{ 0, 0 }, directions{ 0 }
 {
     setDiagonalMovement(false);
     setHeuristic(&Heuristic::manhattan);
@@ -52,11 +52,15 @@ void AStar::Generator::setHeuristic(HeuristicFunction heuristic_)
 
 void AStar::Generator::addCollision(Vec2i coordinates_)
 {
+    verify(coordinates_);
+
     walls.push_back(coordinates_);
 }
 
 void AStar::Generator::removeCollision(Vec2i coordinates_)
 {
+    verify(coordinates_);
+
     auto it = std::find(walls.begin(), walls.end(), coordinates_);
     if (it != walls.end()) {
         walls.erase(it);
@@ -68,8 +72,18 @@ void AStar::Generator::clearCollisions()
     walls.clear();
 }
 
+void AStar::Generator::verify(const Vec2i& v) const
+{ 
+    if ((v.x < 0) || (v.x >= worldSize.x) || (v.y < 0) || (v.y >= worldSize.y))
+    {
+        throw std::out_of_range("Vec2i is out of range !");
+    }
+}
+
 AStar::CoordinateList AStar::Generator::findPath(Vec2i source_, Vec2i target_)
 {
+    verify(source_); verify(target_);
+
     Node *current = nullptr;
     NodeSet openSet, closedSet;
     openSet.insert(new Node(source_));
diff --git a/source/AStar.hpp b/source/AStar.hpp
index d006820..3d86b2c 100644
--- a/source/AStar.hpp
+++ b/source/AStar.hpp
@@ -40,9 +40,10 @@ namespace AStar
         bool detectCollision(Vec2i coordinates_);
         Node* findNodeOnList(NodeSet& nodes_, Vec2i coordinates_);
         void releaseNodes(NodeSet& nodes_);
+        void verify(const Vec2i&) const;
 
     public:
-        Generator();
+        Generator() noexcept;
         void setWorldSize(Vec2i worldSize_);
         void setDiagonalMovement(bool enable_);
         void setHeuristic(HeuristicFunction heuristic_);