Graffiti in Google Maps
Site of an extinct volcano crater, the Cerro Prieto, located near Mexicali in Baja California (Mexico). This image as seen in Google Maps.
Apparently, a lot of visitors to the site have decorated it with their graffiti, drawn huge enough to be seen from high above.
The graffiti appears to have been drawn with the intention of being seen by people looking down into the crater from the eastern rim of the crater. Here's a closeup shot of it, taken from the ground.
A similar volcanic crater in Iceland is also decorated with graffiti of many hikers who have visited it over time.