Lake Kleifarvatn is the largest lake on Reykjanes Peninsula and is a popular recreational fishing ground where people take their fishing poles for a relaxing day by the lake and also for scuba divers exploring the underwater geothermal springs. The lake is about 10 m2 and one of Iceland's deepest lakes with the deepest part reaching 97m. According to folklore the lake is supposed to be a home of a worm like monster the size of a whale. An interesting fact is that the lake has no visible inlet and outlet of the lake like you see in most lakes the reason is that most of the water flows underground. After a big earthquake in the year 2000 a fissure opened at the bottom of the lake and it slowly started to drain and lost 20% of its surface and got nicknamed the "disappearing lake" however in a few years time sediments filled up the fissure and the leak stopped and has now restored its surface area. close to the lake you will also find The explosion crater GrŠnavatn ( e.Green lake) and the high temperature geothermal area Selt˙n with its many mudpots and fumaroles.
The drive along the lake is very scenic and offer many photo opportunities