These caves secretly held national treasures during World War II.

Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.

The location where the iconic movie character declared it was time to go home.

Ancient mysterious ruts carved in the bedrock.

Enigmatic tombs and cave dwellings on the outskirts of a rural village.

The Jesus tree of Malta bears a striking resemblance to Christ on the cross.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Thanks to its curved shape, this incredibly durable dam "whispers" to visitors.

On the wall of this medieval walkway, a symbol of the Spanish Inquisition.

Designed by famed architect Horace King.

Measuring approximately 200 feet long, Swampy is the world's largest alligator-shaped building.

After the attack on Pearl Harbor, rocks and fossils from every U.S. state were collected into a pyramid of national unity.

This huge work of functional public art replaced a landfill in New Jersey's Meadowlands.

Featuring the the longest lift span of any vertical-lift bridge in the world.

A monument celebrating the idea of reaching inaccessible places.

Manatees congregate around a power plant's discharge canal where the water is especially warm.

Visitors flock to see this church tower's unintended feature: It happens to resemble a giant chicken from multiple points of view.

This small museum gives visitors a chance to soak up the history of the "sponge capital of the world."

An author's private collection of quirky travel-trinkets and oddities has become a rotating mini-museum in the window of a local bookstore.

The ruins of an important pilgrimage destination for worshippers of a Maya fertility goddess.

A cemetery in Barcelona's Poblenou district is home to this touching funerary statue, which depicts death in the form of a winged skeleton.

This cemetery features modernist statues as strange as its name.

The unexpectedly beloved remnants of a controversial thermal power plant.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.