Using box collider or rigidbody, to stop object from going through another one.

Hi,

I've designed an object that responds to mouse clicks, let's say, if I click on my terrain via mouse the object moves to that point, on the terrain as well there is another object similar to a wall, the problem is that when i click on the wall the moving object goes through it and it doesn't stop when it reaches it. How can i make the wall solid nothing goes through it, I heard about box collider but didn't work for me. Any help please, I would prefer to use the method of adding rigidbodies and box colliders as they are a lot easier than adding code into my script.

Any help is hugely appreciated.