Joshua Tree National Park 

This desert park is filled with unique desert trees and plants as its name proclaims but even more interesting are the rock formations throughout the park.  The granite rock that underlies much of California was fractured by the continental drift and the San Andres and other faults that are within the park.  These fractures were both horizontal and vertical leaving what seems like G_d playing like a child with a set of gigantic blocks.  Some boulders are as big as houses while others are as small as a bread box.  Many of the camp sites let you get right into the middle of the rock formations.