Near Hafnarfjörður there is the largest lake on the Reykjanes Peninsula called Kleifarvatn. Its area is 9.1 square km. And it is one of the deepest lakes in Iceland, with a depth of 97 meters. It is located in a picturesque place, so many people come there to take beautiful photos.

Kleifarvatn is located in an area with high seismic activity. The landscape is covered with a thick layer of lava, hot springs soar in many areas. There are several active volcanoes in this region. The fact is that the Peninsula is located at the junction of tectonic plates, in the zone of cracks in the Mid-Atlantic Ridge. So volcanic eruptions and earthquakes occur during plate movement.

In 2000, as a result of one of the earthquakes, the lake was damaged. Its volume has decreased by more than 20%. Hot springs also appeared then. This caused great interest in the lake: documentaries were made about it, and scientists from all over the world put forward theories about when the lake would be drained. This event even inspired the Icelandic writer Arnaldur Indriðason to write a novel about how the draining of a reservoir revealed gruesome details about a murder many years ago. But the panic was in vain: in 2008, Kleifarvatn began to fill with water again and has now fully recovered.

Kleifarvatn has no tributaries or outflows: all water entering and leaving it passes through the porous lava rock around it. Despite this, there is a high population of fish, due to which the lake is popular with local fishermen.

Tourists from all over the world come to see the natural wonder. Recently, a new service has appeared for travelers. These are underwater excursions on the lake. During them, divers can see hot springs and feel bubbles while exploring the world between two tectonic plates.