The secret city built by the Manhattan Project.

This bridge is haunted by the ghost of a distraught mother.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

A stairway to heaven, or to nowhere at all.

The haunting ruins of Jack London's dream house.

An enchanting monastery in the Spanish countryside appears lifted from a fantasy tale.

A canvas of crops grow from vibrant red soil in this terraced farmland.

An ice cream parlor chain that caters to vegans and pinball fans equally.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

A rocky sea serpent hides caves, blowholes, and a spectacular natural bridge.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

The attic of a four-century-old canal house hides a clandestine church.

Intensely colorful calcite pools in Southern China.

The oldest church in Iceland is one of the few to feature ornate decoration.

A bike being "eaten" by a tree is the real Vashon legend behind popular children's book, "Red Ranger Came Calling."

This Florida sinkhole hides a rainforest-like micro-environment in its depths.

This amazing pedestrian suspension bridge in the Swiss Alps would give Indiana Jones nightmares.

Wonderland replication in progress by one persistent man.

What was once one of the country's largest confectionary plants is now an abandoned ruin, but is still pretty sweet.

A cave's rare beauty held a cavernous secret hidden underground.

This hobbit-y little hot spring may be the oldest spring used by humans in all of Iceland.

Caves famous for the dragon-slaying saint who lived there.

The only remnant of a small mining town is an abandoned railroad tunnel that is steeped in ghostly lore.