City of Rocks State Park in New Mexico is known for towering sculptured rock formations in the Chihuahuan Desert, created when a massive volcanic eruption 34.9 million years ago laid down the Kneeling Nun Tuff and erosion later carved it into isolated pinnacles and boulders. The landscape was used by the Mimbres people from about 750 to 1250 AD, and traces of later Spanish and Butterfield Overland Mail Route travelers also remain. Established as a state park in 1953, it is valued for its striking geology, evidence of long human use, desert plants and wildlife, recreation, and exceptionally clear night skies recognized by its International Dark Sky Park designation.