Milford Sound, New Zealand
Rudyard Kipling called Milford Sound the "eighth wonder of the world," and if you visit this region of New Zealand, you'll see why. Formed by glaciers during the Ice Age, the landscape around Milford Sound still bears evidence of its creation in the form of epic scenery: Cliffs rise from fjords crowned by mountains and waterfalls.
The best way to see Milford Sound is via boat. Take a sightseeing cruise on the fjord to see waterfalls and wildlife such as dolphins and penguins. Or navigate the waters under your own steam on a kayaking tour.
Once you've experienced the water from the surface, go underneath with a visit to the Milford Discovery Centre and Underwater Observatory. This is the only floating, underwater observatory in New Zealand, and visitors can go more than 30 feet deep (while staying dry) and get 360 degrees of the underwater environment.