The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

This amazingly preserved Gold Rush town is a historian's dream.

This former coal gasification plant found a curious second life as a popular public park.

A museum dedicated to the history and exploration of both popular music and science fiction.

A giant Troll lurks under one of Seattle's oldest bridges.

One of the greatest boxers and humanitarians to ever live chose his hometown as his final resting place.

The world's longest known cave system.

This handsome giant is said to mark the birthplace of the mythical woodsman and even had a cameo in a Stephen King novel.

The eccentric mansion of one the most popular horror authors of modern times.

Yo, Adrian!

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

A fully functional, 200-year-old remnant of the time when Brixton was mostly fields.

A Victorian park cemetery, standing on the site of what was once the Great North Wood.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

An extraordinary "City of Caves" carved from solid stone.

The mysterious empty cupola behind the monumental arch points to an ancient prophecy of Delhi.

A blooming house of worship for the masses.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

The walls and streets of the ancient city are peppered with penises.

Erotic art covers the walls of the largest ancient pleasure palace.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.