Destroyed by flood waters, prison now serves as a training ground for armed forces.

The growing stones of Romania.

A natural arch offers panoramic views of Yangshuo's karst hills.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

There are more than 4 million bricks inside this unofficial Lego museum in a former middle school.

This historic observatory contains the world's oldest refracting lens telescope.

Where giant ships go to die.

Secret North Korean passage discovered below the world's most dangerous border.

A cherry tree growing atop a mulberry tree.

Strange physical sensations and optical contradictions keep visitors coming back for more.

Ancient rock-hewn town that witnessed key events of Georgian history.

A whimsical tower with a spiral staircase, inspired by the Space Age and the Möbius strip.

Museum preserving torture methods from the past.

Temple of a million beers.

Mount Nyiragongo has erupted at least 34 times since 1882 and is home to the world's largest lava lake.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Cursed swimming pool left abandoned is now a favorite of filmmakers and ghost hunters.

Enormous lake at the bottom of a unique cave system.

Green labyrinth formed by a karstic maze hidden in a preserved oak forest.

Marked by the hand of the explorer Henry Morton Stanley.

Personal garden filled with mosaics made of recycled garbage.

Dive bar built out of the remains of a whaling ship.

Small island science organization offers public the chance to participate in research.

A 140-year-old castle with underground caves hidden in San Francisco.