Where else in the world besides Iceland can you scuba dive at the fault line between two tectonic plates? Nowhere. That unique activity is far from the only exciting reason to visit the Nordic nation of fire and ice. The former comes in the way of secret hot springs (found while hiking Reykjadalur Valley) and trekking through lava fields, tubes, caves and a desert of black ash. The latter is experienced via snowmobile or riverjet, ice cave exploration or glacier hiking. The otherworldly possibilities are endless at Ion Luxury Adventure Hotel, especially the wintertime grand finale: the Northern Lights spectacle.