Have you ever been up to Mono Lake (north of Mammoth Mountain in Northern California) and seen the tufas? Tufas are calcium carbonate, or limestone and they took decades to centuries to grow under water. It is a weird lake because it is too salty and devoid of oxygen to support fish. There is nothing living in the lake but an alkaline fly and some brine shrimp, but those two things manage to feeds millions of nesting birds a year. So, tufas are only created in the water, but since LA sucked all the water from Northern CA for a while unchecked, Mono Lake lost water levels and the tufas were uncovered. They are like fairy or mermaid castles and you can walk around them and snap photos. (one looks like a camel to me) Check them out.
Here is a link in case you want to read more about Mono Lake and its surreal tufas.