diff --git a/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Cell.java b/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Cell.java
index 33c9d89..ef674b2 100644
--- a/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Cell.java
+++ b/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Cell.java
@@ -7,27 +7,18 @@ public class Cell {
 
     private final Point pos;
     private final JLabel content;
-    private boolean selected;
     private boolean wall;
 
-    public Cell(Point pos, JLabel content) {
+    Cell(Point pos, JLabel content) {
         this.pos = pos;
         this.content = content;
     }
 
-    public boolean isSelected() {
-        return selected;
-    }
-
-    public void setSelected(boolean selected) {
-        this.selected = selected;
-    }
-
     public boolean isWall() {
         return wall;
     }
 
-    public void setWall(boolean wall) {
+    void setWall(boolean wall) {
         this.wall = wall;
     }
 
diff --git a/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Grid.java b/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Grid.java
index cfe2eb9..2b72b03 100644
--- a/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Grid.java
+++ b/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/model/Grid.java
@@ -56,10 +56,10 @@ public class Grid implements Iterable<Cell> {
         content.revalidate();
     }
 
-    public void setWall(Point loc) {
+    public void setWall(Point loc, boolean wall) {
         final Cell c = cells.get(loc.x + size.width * loc.y);
-        c.setWall(true);
-        c.getContent().setBackground(Color.BLACK);
+        c.setWall(wall);
+        c.getContent().setBackground(wall ? Color.BLACK : null);
         c.getContent().revalidate();
     }
 
@@ -67,7 +67,6 @@ public class Grid implements Iterable<Cell> {
         for (Cell cell : cells) {
             cell.getContent().setBackground(null);
             cell.setWall(false);
-            cell.setSelected(false);
         }
     }
 
@@ -75,4 +74,5 @@ public class Grid implements Iterable<Cell> {
     public Iterator<Cell> iterator() {
         return cells.iterator();
     }
+
 }
diff --git a/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/ui/App.java b/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/ui/App.java
index 9d40c78..3083003 100644
--- a/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/ui/App.java
+++ b/simple-pathfinding/src/main/java/fr/uha/gasser/pathfinding/ui/App.java
@@ -24,6 +24,7 @@ public class App extends JFrame {
     private Node startNode;
     private Node endNode;
     private JPanel gridPane;
+    private boolean wallPlacing = false;
 
     private App() throws HeadlessException {
         super("Pathfinding");
@@ -34,6 +35,7 @@ public class App extends JFrame {
     }
 
     private void setupInterface() {
+        setDefaultCloseOperation(EXIT_ON_CLOSE);
         gridPane = new JPanel();
         gridPane.setLayout(new GridLayout(ROWS, COLS));
         for (Cell c : grid) {
@@ -45,7 +47,9 @@ public class App extends JFrame {
             public void mousePressed(MouseEvent e) {
                 final JLabel at = (JLabel) gridPane.getComponentAt(e.getPoint());
                 final Point loc = grid.get(at).getPos();
-                if (startNode == null) {
+                if (wallPlacing) {
+                    doPlaceWall(loc);
+                } else if (startNode == null) {
                     grid.setColor(loc, Color.RED);
                     startNode = new Node(loc);
                 } else if (endNode == null) {
@@ -56,6 +60,9 @@ public class App extends JFrame {
         });
 
         final JMenuBar menuBar = new JMenuBar();
+        final JMenuItem placeWallItem = new JMenuItem("Place wall");
+        menuBar.add(placeWallItem);
+        placeWallItem.addActionListener(actionEvent -> setWallPlacing(placeWallItem));
         final JMenuItem runItem = new JMenuItem("Run");
         menuBar.add(runItem);
         runItem.addActionListener(actionEvent -> doSearch());
@@ -70,6 +77,24 @@ public class App extends JFrame {
         getContentPane().add(gridPane);
     }
 
+    private void setWallPlacing(JMenuItem placeWallItem) {
+        // Invert selection state
+        placeWallItem.setSelected(!placeWallItem.isSelected());
+        final boolean selected = placeWallItem.isSelected();
+        if (selected) {
+            placeWallItem.setBackground(Color.BLUE);
+        } else {
+            placeWallItem.setBackground(null);
+        }
+        this.wallPlacing = selected;
+    }
+
+    private void doPlaceWall(Point loc) {
+        final boolean wall = grid.get(loc).isWall();
+        // Toggle "wall" state
+        grid.setWall(loc, !wall);
+    }
+    
     private void doReset() {
         pathfinder = null;
         startNode = null;