This centuries-old tree tells an unusual tale of vegetation and fertility in the desert.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Museum precariously perched on a massive yellow pillar.

Where Agatha Christie mysteriously disappeared in 1926.

The largest greenhouse in the world is home to over one million types of plants.

Nuclear waste dump site now an environmental sanctuary.

Seat of the Duke and Duchess of Devonshire for centuries.

Museum in a swimming pool where the water still flows.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

Rustic natural hot springs in the deciduous rain forest.

20,000 pieces in a Frank Gehry-designed building.

Many cities have held the title, but Brazil snatched the crown from Chile in 2011.

Little Red Lighthouse under the George Washington Bridge.

One of Japan's most famous sights, the bridge was originally built in 1673.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

Supposed home of the camel ridden by Napoleon during his Egyptian campaign.

The Dalai Lama named this New Zealand landscape the "Spiritual Center of the Universe."

Highly spherical boulders on the shores of New Zealand.

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

Huge hole looks down onto an underground beach populated with sea lions.

Sloth rehabilitation center in the jungle of Costa Rica.

At 8,000 feet, the world's highest tea estate draws visitors for both its products and its panoramic views.

On the outskirts of a desert trading village high on the Andean plain, steel giants have been destroyed by salt winds.