There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This mysterious Bronze Age standing stone has become a place where couples profess their love.

This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

Famous for its bio-luminescent inhabitants, known as "Dismalites" .

148 feet long and in the middle of a verdant forest.

An ancient Phoenician citadel once stood at the site where Queen Dido first landed, according to legend.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

This isolated structure beckons adventurers with sublime views of the Faroe Islands.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

The remains of a magnificent medieval fortress that was the capital of a vast empire.

The last remaining predreadnought battleship in the world has been a museum for nearly a century.

An otherworldly restaurant perched on the edge of a jagged cliff next to a medieval holy city.

This abandoned bridge to nowhere stands secluded in the woods of a Cleveland suburb.

One of the oldest seagoing boats in the world can be found at the Dover Museum.

Stop by to view a fleet of handmade kayaks, all modeled on traditional Arctic hunting vessels.

A decommissioned military complex that's now a modern industrial park.

This "living building" on Georgia Tech's campus is home to a blueberry orchard, honeybees, and more than 900 solar panels.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

Enormous sandstone towers loom within a Czech forest.

Local legend says Isaac Newton built this footbridge without any screws, bolts, or nails.

This Scottish castle has witnessed clan rivalries, Jacobite uprisings, whisky smuggling, and more.

A mesmerizing wonderland of salt-encrusted tree branches and pencil roots.

A rare example of this century-old British tank stands near the center of town in Ashford.