The road to Mt Rushmore, granite mountains, winding roads and forests...

 And then you take one of the mountains, apply a design, some dynamite, a whole lot of man hours, a grand walkway, and the flags of all states... and you have...

 A really big impressive monument... And while the idea of carving an amazing piece of nature into the busts of four presidents may seem a little odd, it really is an incredible sight to see.