An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

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

The oldest stone house in Paris was built by its most famous alchemist.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

The first green space constructed on an elevated viaduct.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

A white oak with property rights.

A series of waterfalls and pools that flow through the 'Ohe'o Gulch and into the ocean.

Walk in the footsteps of the gods and straddle two tectonic plates.

The glowing blue Nymphaeum of Emperor Tiberius.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

This legendary city has been a tourist attraction for centuries.

Seat of the Duke and Duchess of Devonshire for centuries.

An ancient knight and a symbol of the city's freedom.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

The largest greenhouse in the world is home to over one million types of plants.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Five candy-colored villages on the Italian Riviera.

The hallucinogenic center of the ancient world.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A heavenly experience, right here on Terra Firma.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Iceland's largest lagoon is home to stunning multi-colored icebergs.