If you have a few hours of layover in Reijkavik, I highly recommend taking the 20-minute bus ride to the Blue Lagoon medicinal hot springs. The short ride takes you through fields of dark lava rock, and once you’re there, you will be handed a bracelet that will allow you to program your locker and purchase beer at the waterside bar. The lagoon itself is a flat expanse of steaming pastel blue — silica, potassium, calcium, magnesium and various algeas all mixed in with geothermal seawater. The silica deposits make everything underfoot, down to the wooden steps, smooth and white.