National Geographic's Photo of the Day
This is not strictly cactus related, but it is in a desert, so, you know, close enough, because, you know, Wow.
Petroglyphs, Aïr Mountains Mountains, Niger, 1999
Photograph by George Steinmetz
These 2,500-year-old petroglyphs, portraying figures with tulip-shaped heads and hourglass bodies, mark an ancient human presence in the Sahara desert’s Aïr Mountains.