Strange lava formations in Lake Myvatn. Myvatn translates to Mosquito-lake. The reason for this is the large number of mosquitos that live near the lake. These mosquitoes don't sting, but they swarm around you and fly into your ears, eyes, nose and mouth.
There is a local myth about the creation of the lake: When god had created the world, the devil was furious at its splendor. He tried to extinguish the sun by pissing at it. He missed, and the result of the attempt became Lake Myvatn. I guess that says something about what the locals think of the lake.