The ruins of an 11th-century Norman castle with a rare, perfectly circular shape.

A mesmerizing reservoir nestled at the heart of a pre-Islamic Yemeni village.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The water here is so clear you can see the mysteriously sunken ship from the surface.

This beautiful arched gate is all that remains of the fortress the ancient mountaintop town of Amadiya once was.

Modern commuters still pass through this 2,000-year-old Roman archway.

A meandering boardwalk across the bogland leads to a "stairway to heaven" with sublime views.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

The weathered grave of a medieval anchoress who walled herself up in a cell attached to a church.

The largest library in Latin America owes its existence to an Old World earthquake and a Napoleonic invasion.

Folklore says this medieval fortress was plopped atop a portal to hell to trap the demons below.

Western Europe's only representation of a Roman goddess still in its original location sits in an unassuming park.

The construction of a tram line unveiled hidden remnants of the old medieval city.

Some locals believe the fabled lost gold of General Yamashida is hiding somewhere beneath the city.

A 1,500-year-old, 3-story subterranean city where ancient Persians took refuge in times of war.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

This 700-year-old Cyprus castle is the birthplace of the world's oldest wine, said to be toasted by Richard the Lionheart at his wedding.

The ancestral home of beloved English poet Lord Byron has a bizarre history.

This romantic, decaying 13th-century ruin on the edge of Sherwood Forest is reputedly one of England's most haunted places.

A magical place that lets you play in and explore the world of Studio Ghibli.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

Dead weights honor the dead of Portugal's fishing industry.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

An abandoned giant glass dome sits in the bay in “the Venice of the East.”