Indian Petroglyphs National Monument is one of the nation's newest, established in 1990, so it has not been 'protected area' for very long.

Some of the etchings visible here on the rocks may be as much as 3,000 years old, but petroglyphs and other rock carvings cannot actually be dated with any kind of accuracy.  Dating is always an educated guess.  Other markings are clearly recent:  there are Christian religious symbols as well as cattle- and sheep-brands, and, of course, there are a few "Mike was here" additions as well.

The area is actually five cinder cones of ancient volcanoes.  The slopes are steep and uneven, and the ground is gravelly, making for uncertain footing.

Note the sign at the trailhead warning the adventuresome against using bikes, roller blades, and skateboards on the trail...  as if such things might actually be possible.