The first archaeological site discovered by aerial photography.

A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

Europe's largest prehistoric mound – burial site of a legendary king?

The longest hedge maze in the world.

Museum about life, death, and cannibalism in the Stone Age.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

The Bristol Camera Obscura housed in an ancient windmill.

Famously misunderstood wonder of the ancient world

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

The largest of London's subterranean rivers and once a mad, bad center of London life.

An unusual round church in London with a Templar past.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

The only recreation of William Shakespeare's indoor playhouse.

An unknown Hall of Fame in Jackson, Tennessee.

A natural history museum with an extensive collection of bird dioramas.

These ancient ritual mounds are our best window into the culture of the ancient Mississippians.

The secret city built by the Manhattan Project.

Enormous lake at the bottom of a unique cave system.

The world's longest known cave system.

This simple, broken column marks the final resting place of one of America's most famous explorers.

This structure among the trees was the result of divine inspiration.

Visit this playground of waterfalls, caves and sinkholes.

The small cave that housed Tennessee's "first citizen."

All you ever needed or wanted to know about America's favorite whiskey, but not a drop to drink.