These 12th-century catacombs carved into a mountainside were a place of mysticism and Christian hermitages.

A Danish fisherman spent 25 years covering nearly every inch of his home with tens of thousands of shells as a gift to his wife.

This Danish park has celebrated the American independence day since 1912.

Nearly 40 miles and 1,000 years of limestone mines under Denmark.

A walkable map of the world, made from soil and stone by one man.

Denmark’s never-ending bridge.

This colorful artistic feature atop a Danish art gallery allows visitors to stroll through a rainbow.

This legendary dive bar boasts a collection of over 1,300 clown figurines.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

One of the most well-preserved castles in Italy also contains a rare medieval example of a port fortification.

One of the oldest libraries in the world is still operating and contains the oldest existing document in the Italian language.

These elaborate gothic monuments honor Verona's medieval lords.

It’s said this crypt was the setting for the tragic finale of the Shakespeare play.

Pilgrimage site for star-crossed lovers.

Since 1969, this restaurant has served up dishes typical of Istanbul's Greek diaspora.

A small but immensely extravagant palace built by the "Night King."

Walk inside a half mile long crevice right outside the town of Garmisch Partenkirchen.

This airport currywurst stand is made out of retro airplane parts.

A subterranean display of public art and architecture.

German-style coffee and cake, just like Oma used to make it.

One of the most easily accessible examples of the rare 1960s UFO houses.

A saintly relic hidden in a Prague church basement.

Archduke Ferdinand II's collection of rare objects is considered one of the oldest museums in the world.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.