The castle still holds traces of the abandoned Roman fort it was built atop.

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

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

This cheese shop also houses a museum devoted to Dutch dairy.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Lavish royal estate punctuated with heated greenhouses.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Baroque celebration of the end of the Great Plague of Vienna.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

The final resting place for the remains of 143 Habsburg royalty.

A shrine built to combat the bad karma of a commercial venture.

Singapore's oldest Hindu temple.

This Buddhist temple is home to the graves of the Japanese national legends, the 47 Ronin.

Someone left a Boeing 737 in a field in southern Bali.

A small subculture of boat dwellers keep their traditional way of living alive at this Hong Kong Typhoon Shelter.

Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

This tourist village in Nairobi celebrates the traditional lifestyles and customs of Kenyan tribes.

The world’s largest permanent desert lake is a UNESCO World Heritage Site.

Island, once a pirate hideout, now home to an abandoned resort.

Famously misunderstood wonder of the ancient world