diff --git a/src/util/graph/Graph.h b/src/util/graph/Graph.h
index 2a3b2ed..09d0465 100644
--- a/src/util/graph/Graph.h
+++ b/src/util/graph/Graph.h
@@ -19,7 +19,7 @@ namespace graph {
 template <typename N, typename E>
 class Graph {
  public:
-  ~Graph();
+  virtual ~Graph();
   virtual Node<N, E>* addNd() = 0;
   virtual Node<N, E>* addNd(const N& pl) = 0;
   Edge<N, E>* addEdg(Node<N, E>* from, Node<N, E>* to);