Peek through a transparent pyramid and drink in the mountain made of books.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

The hallucinogenic center of the ancient world.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Roman ruins top white travertine terraces formed by ancient hot springs.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

Stalactites and stalagmites in a beautifully lit cave.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

A Hawaiian stairway to heaven—that you can't climb.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

These azure waters were thought to lead to the Mayan Underworld.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

An underwater city for the dead.

An homage to everyone's favorite prehistoric cartoon family.

Centuries-old bridges grown from tangled roots.

An alchemist's "magic door" stands in the middle of a Roman park.

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

A 30-acre garden inspired by the principles of modern physics.

Stroll through a wonderland of stupendous moss-covered trees.

One man's homage to the sun continues to grow like a glass fractal.