Collapsing castle on the Hudson river was once the storage site of military surplus business.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

A semi-scholarly approach to sex.

Try not to get slimed in Tribeca.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A terrific purveyor of natural history objects and curios.

This psychedelic tourist trap is a leisurely descent into madness.

Snow-capped peaks, colorful waterfalls and stunning vistas on the edge of the Himalayas.

This Tang Dynasty behemoth is the biggest Buddha in the world.

These layered sandstone mountains in China look like they are made of pressed crayons.

A total of 999 stairs lead visitors through a massive hole in a mountain known as the Gateway to Heaven.

The most famous location in China was home to whole dynasties worth of imperial rulers.

This abandoned fishing settlement may well be the greenest village in the world.

This vertical pinnacle in China was the inspiration for the floating mountains in the movie “Avatar.”

A part of the world's largest marsh seems to be growing bright red Martian grass.

This amazing oasis of art and plants is hidden on the outskirts of Marrakesh.

This 15th-century church houses priceless works of art from a range of Croatian artists.

Just a few miles from Novalja, a strange geological oddity has left scientists baffled.

This abandoned Croatian stronghold never saw a great deal of conflict but it is still a beloved relic nonetheless.

This military tunnel dates back to World War II and provides visitors with a little wartime adrenaline.

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.