Tufa spires and tower formations of calcium carbonate at sunset, Mono Lake, South Tufa Reserve, Mono Basin Scenic Area, Lee Vining, Inyo National Forest Scenic Area, California, United States of America, North America

Tufa spires and tower formations of calcium carbonate at sunset, Mono Lake, South Tufa Reserve, Mono Basin Scenic Area, Lee Vining, Inyo National Forest Scenic Area, California, United States of America, North America

Tufas of calcium carbonate, Mono Lake State Reserve, California, USA

Tufas of calcium carbonate at lake in Mono Lake Tufa State Reserve, with mountains in the background, in California, United States of America, North America

Tufa spires and tower formations of calcium carbonate at sunset, Mono Lake, South Tufa Reserve, Mono Basin Scenic Area, Lee Vining, Inyo National Forest Scenic Area, California, United States of America, North America

Tufas (calcium carbonate), Mono Lake, Tufa State Reserve, California, USA, North America

Tufas of calcium carbonate surround lake in Mono Lake Tufa State Reserve, with snow capped mountains in the background, in California, United States of America, North America

Tufa spires and tower formations of calcium carbonate, Mono Lake, South Tufa Reserve, Mono Basin Scenic Area, Lee Vining, Inyo National Forest Scenic Area, California, United States of America, North America

Tufas of calcium carbonate, Mono Lake State Reserve, California, USA

Calcium carbonate tufas, Mono Lake, California, USA, North America

The Trona Pinnacles are pictured on a hot summer day in Trona, Calif., on June 7, 2015. The unique formations, known as tufa towers, are primarily made of calcium carbonate and were formed when the springs interacted with the water in what was once Searles Lake.