The Blue Lagoon is Iceland’s most iconic attraction — a surreal, milky-blue geothermal pool set amid a stark, black lava field on the Reykjanes Peninsula. The water, a byproduct of the nearby Svartsengi geothermal power plant, is rich in silica, algae, and minerals that give it its signature opaque blue color and are believed to have beneficial effects for the skin. With water temperatures averaging 37 to 39 degrees Celsius, soaking in the lagoon is a blissfully warm experience even in the depths of an Icelandic winter.

The facility has evolved from a simple bathing spot into a world-class spa complex, complete with an in-water bar, silica mud masks, a restaurant serving Icelandic cuisine, and the luxury Retreat Hotel. Located just 20 minutes from Keflavík International Airport, it makes an ideal first or last stop on an Iceland trip.

Pro tip: Book well in advance, as walk-ins are no longer accepted and slots sell out weeks ahead during peak season. The first morning entry or the last evening slot tend to be the quietest. If visiting in winter, the late afternoon slot offers the magical combination of twilight skies, steam, and the possibility of aurora overhead.