Mono Lake is a large, but shallow soda lake in Mono County, California, United States. Formed 760.000 years ago, the lack of an outlet causes high levels of salt in the lake, which makes the water alkaline. The lake has no fish, but instead loads of brine shrimps and alkali flies. Around the lake are many tufa formations. Tufa is essentially common limestone, but the way of its formation is different.