It&rsquos a different world underwater, whose capital lies somewhere in Iceland. In Thingvellir National Park, in Selfoss, you can go snorkelling between two continents. This is because every year, two tectonic plates in the Golden Circle route drift apart, creating a beautiful rift valley called the Silfra fissure. So technically, you&rsquod be swimming between the Eurasian and North American continental plates.