A 100' aerial view overlooking the Valley of the Names north of Winterhaven, California.  The site is also known as Graffiti Mesa.  From an online article:

For over seventy years, people have been driving out in their RVs to a remote desert area near the city of Yuma, in the US state of Arizona, to write their names and leave messages on the desert floor. Unlike regular graffiti that is hurtful to the environment, at Valley of Names messages are spelled out by carefully arranging rocks and small boulders in the hard-packed white sand.

The practice probably began during the Second World War when U.S. Army General George Patton brought his soldiers to this flat rocky area to train. This training camp, known as the Desert Training Center, was the largest military training ground in the history of military maneuvers. The camp grounds stretched from the outskirts of Pomona, California to within 50 miles of Phoenix, Arizona, and from the suburbs of Yuma to the southern tip of Nevada.

The earliest messages were probably made by the soldiers and the area took the name of Graffiti Mesa. After the war, the area was rediscovered and by the 1960's the tradition had become a rite of passage for local off-roaders. In the 1970s, what was a four-acre area with a few hundred names swelled to thousands of names spread over 1,200 acres of the desert floor.

Every few years a team of volunteers would go out to clear away debris from the desert winds and replace rocks that might have been washed away in a storm. These messages are precious; some of them are over fifty years old.

Earlier there was plenty of lava rock on the east side of the hill to work with. Now they are all used up and visitors have to haul their own rocks to create the graffiti. There are some who have been coming back to this site for more than 20 years.

Look in the distance to see the striking Picacho Peak due north.

From: https://www.amusingplanet.com/2018/05/the-valley-of-names.html