A closer look a Mono Lake was a necessity. The south tufa area (pay entrance) is located just off Hwy 120 and offers interpretive walks along the south shore. Looked like a great place to get some good shots of the towers. However, being short on time, I decided to continue on to Hwy. 395 and drop by the public access entrance to the west tufa area (free). Mono Lake is the oldest lake in North America and estimated to be over 700,000 years old. The tufa are formed by freshwater springs, which produce calcium. When the calcium is combined with the alkaline and carbonates of the salty lake water, limestone is formed. Over a period of years, the limestone is formed around the mouth of the spring, which creates the tower. As the lake receeds, the tufa towers are further exposed.