7. Devon Island, Canada
Devon Island in Canada is known as a "polar desert," according to NASA. The ice-covered island is the largest uninhabited piece of land on earth. Devon Island has such extreme temperatures that no one has inhabited it since the 1930s or '40s. Today, the island is used for NASA research because it mimics the conditions on Mars. The space program tested equipment and spaces suits on Devon Island before sending them into orbit.
8. Son Doong Cave, Vietnam
The Son Doong Cave in Vietnam's Nha-Ke Bang National Park dates back to prehistoric times, and it was only rediscovered in 2008. It was first discovered in 1990, and then the location was lost until the mid-2000s. This picturesque cave is the world's largest natural cave, and it was formed around three million years ago. The cave was finally opened to the public in 2013, and it is a popular tourist destination because of its natural beauty.