Go inside a revolutionary, cage-less zoo where 70 species of monkeys roam free alongside their human visitors.

A miniature city, once ruled by the Queen of the Netherlands.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

Invisible bridge parts the waters, invoking biblical images and preserving the ominous feel of an ancient moat.

This Transylvanian church has changed its denomination four times.

This massive underground salt mine now holds a sci-fi theme park in its depths.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Roadside display for a popular fruit and vegetable stand.

One of the first big sculptures anywhere in Australia.

A giant Australian fruit and tropical farm.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

Come for the flowers, stay for the bats!

This massive water spout has been luring visitors for hundreds of years, some to their death.

Living fossils in this remote Australian bay provide a glimpse of what Earth may have looked like 3.5 billion years ago.

Microscopic fossils suggest Australia may be the birthplace of sulphur-based life forms.

This trio of Australian rock spires may have inspired aboriginal legend or just modern tourism.

Nine limestone rock stacks on Australia's "Shipwreck Coast."

Alien rock formations grown from the sands of an Australian national park.

A massive stairway that almost wasn't leads to one of Australia's most scenic vistas.