One of Iceland's most popular hot springs is the Blue Lagoon, a huge lake of bright blue seawater just outside Reykjaik.Surrounded by volcanoes and lava fields, the Blue Lagoon receives more than 300,000 visitors a year.After a long day's sightseeing or a long night of partying, visitors can relax their muscles and release their tension in the lagoon's steaming hot water, which has an average temperature of about 38 degrees (100℉).Some believe the waters are able to cure certain illnesses and improve skin quality.