Nauthólsvík Geothermal Beach is a hidden gem tucked away along the Ægissíða bike and walk path in Reykjavík. With over half a million visitors each year, this beach is the perfect destination for a sunny summer day. Not only does it offer a warm lagoon, but it also has a sauna, two pools, changing rooms, showers, and a service center with towel and swim-suit rentals and refreshments. During the summer, access to all facilities is free, and there's a small fee during the off-season. You can relax with a book, go for a swim, or picnic on the sand. After a day at the beach, check out nearby environmentally-certified restaurant Nauthóll or Perlan for some stunning views of Reykjavík and delicious gelato.