The mysterious fingers of stone poking from the blue water of California’s Mono Lake have a scientific explanation—they’re limestone deposits called tufa left by calcium-rich springs that bubbled up into the alkaline lake water. But to visitors, the blend of colors and textures can seem more mystical than geological. Recognizing the fragile beauty of the area 13 miles east of Yosemite, the state established the Mono Lake Tufa State Reserve in 1982. Twenty-five years later, the reserve still amazes visitors. You can join a guided tour, offered at 1 p.m. daily in September and on weekends in October. (760) 647-6331, www.parks.ca.gov.

Can’t get there? Here’s another
A tufa tower the size and shape of an Egyptian pyramid rises from the blue waters of PYRAMID LAKE, 36 miles northeast of Reno. The warm lake is a great place to go for a swim on a balmy autumn day. (775) 476-1155, www.plpt.nsn.us.