The Blue Lagoon is a unique wonder of Iceland, a result of all that volcanic activity the small island is so famous for. In the middle of the weird and wonderful, flat black lava fields of the Svartsengi National Park, the huge, outdoor lagoon is filled by naturally heated geothermal water which comes from 6,500 feet (2,000 meters) below the surface of the earth. It is full of minerals, silica and algae and is especially good for the skin and relaxation. In fact, part of the Blue Lagoon development is a health clinic specializing in cures for psoriasis. The water is almost startlingly blue in color, and the white of the silica on the black lava rocks around the edges makes an amazing contrast.