Mono Lake — as it exists today — is in the distance. But at one time it was so big and deep that the shore would have been close to where this photo was taken, rather than the 8.5 miles away that it is today. Hundreds of feet deeper, too.
So what happened? It’s a terminal lake, meaning that water flows into it, but it doesn’t flow out. And since this is an arid climate, the heat slowly evaporated hundreds of feet of water over the course of thousands of centuries (dating back some 760,000 years), until the city of Los Angeles began diverting some of the meager water sources for the lake back in 1913.
After that, the evaporation quickly outstripped the inflow of water and the lake level plummeted until legal action reversed the process in 1994. Since then the lake level has slowly been increasing. You can read more about it here and here.