The Seven Sisters Waterfall, Geirangerfjord, Norway. The two most notable waterfalls in the Geirangerfjord are the Seven Sisters and the Suitor. The falls face one another across the fjord, and the Suitor is said to be trying to woo the sisters opposite.
Explore the ancient caves of Hang Son Doong, Vietnam. Hang Son Doong is one of the largest caves in the world and features a fast-flowing underground river. For spelunkers, exploring Hang Son Doong is the equivalent of scaling Mount Everest.