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.
Cameron Falls Alberta, Canada Incredibly rare moment: a waterfall turned tomato soup red. The red coloring of the water is a result of heavy rainfall washing sediment (with large quantities of argolite) into the river.