The vast, legendary catacombs hold secrets much stranger than stacked bones.

A unique underground structure dating back to the 1st century BC.

An often-shuddersome journey into a low-tech, robotic themepark.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

The Nobel-Prize-winning author of The Stranger is buried beneath a simple gravestone in a sleepy French village.

Walk through living pictures and music in the Cathedral of Images.

These medieval ruins have survived since the 12th century, even providing shelter from the Nazis.

Series of underground houses inhabited continuously for centuries.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

One man's desire to transcend art led to the construction of this outsider chapel.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

Less a museum than a bizarre fantasy world created by artists and engineers.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

This eclectic, mosaic-clad home includes a bamboo ping-pong loft and a "Whispermaphones" intercom.

The upstairs reading room is packed with millions of rare books, literary manuscripts, and historical treasures.

A view-altering observatory at the University of Texas.

Just like the real 36th president of the United States, animatronic LBJ amuses visitors with jokes and stories.

A tribute to the "toughest woman on the Texas frontier," who survived a famous battle and five husbands.