Cadillac Ranch is near Amarillo, Texas and was built in its original location in 1974. It was moved to its present location in 1997 to move it further away from the growing city. It consists of 10 Cadillacs half buried in the ground at the same angle of the Great Pyramid of Giza in Egypt. It is encouraged to climb on and paint the cars with the numerous spray paint cans they are laying around. Of course I participated.
http://en.wikipedia.org/wiki/Cadillac_Ranch