Cathedral carved out of salt, located a mile below the earth's surface.

A 10 million-ton rock once worshiped by the Tahamies Indians, accessed by an astounding staircase.

The Andean town where every single building is decorated with a brightly colored frieze.

A dangling church built over a Colombian gorge.

After Christopher Columbus died, his son built a fancy house to rule from.

The oldest colonial fortress in the Americas was once the home and later prison of Christopher Columbus.

Built in 1512, the oldest cathedral in the Americas.

Renowned restaurant tucked in a cave once occupied by buccaneers.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

An 11th-century runestone decorates the halls of Terminal 2 of this Scandinavian travel hub.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

It houses the remains of a 17th-century version of the Titanic.

The library's graceful rotunda is like a bibliophile's temple.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This massive library holds what was once the largest book collection in the world.

One of the oldest theaters in Australia, it's also said to be haunted by a performer who died on stage.

You'll find the little birds tucked within the rocks of this Australian beach.

This historic Melbourne bullet factory is fully encased in a massive glass and steel cone.

A fake medieval village in the middle of Turin.

The farmhouse owned by the Danish author who wrote "Out of Africa" is now a museum honoring her legacy.

This colonial fort is an intriguing example of Renaissance military architecture.

Life and death are on parade at the most reliably perilous site of “the Great Migration.”

Get tall with nature's lankiest beasts and their warthog friends at this Kenyan preserve.