Around A.D. 1500, ancient Lake Cahuilla was one of the largest freshwater bodies in North America. Around this oasis, the Desert Cahuilla Indians created a rich and industrious society, building ceremonial rock rings and staging camps and villages along the steadily receding shoreline, before the lake dried up completely by 1541. They also built innovative stone structures to help them harvest the lakes’ fish schooling along the shore. Fish Traps is now part of Anzo-Borrego Desert State Park.