The plague quarantine island home to the alleged "Vampire of Venice."

It's said this geological anomaly was caused when the Devil took a bite out of the Irish mountainside.

A mysterious Neolithic tomb is perched along the edge of a modern golf course.

Ancient Bronze Age rampart that was used into the middle ages.

Huge standing stones mark a site of megalithic mystery.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

Portugal's National Pantheon has a history of curses, collapses and financial problems.

One of the smallest bookstores on the planet.

A garden in Lisbon filled with giant porcelain creatures.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A tiny, heartwarming piece of art hiding in plain sight.

Be on the lookout for the symbolic insect all over the city.

A tiny, hidden alleyway dedicated to the father of meteorology.

Despite having a dome made of papier-mâché this tiny observatory has survived for over a century.

These lovely Turkish-styled baths were brought back to life after winning a reality show competition.

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.

This Manchester laundromat is hiding something.

Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

The home of Ireland's last leprechauns is officially protected by the European Union.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

The lengthy skeleton of one of the tallest Spaniards of all time is on display in Madrid.