This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

A striking symbol of the Bulgarian capital.

This historic black and white monastery is one of Bulgaria's architectural jewels.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

A curious collection dedicated to human and animal anatomy and pathology.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Eighty million natural history specimens call this gargantuan museum home.

The world's largest collection of witchcraft regalia.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

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

A huge musical instrument played by the ocean.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

The Devil’s own choice when he needs a drink in Brussels.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

Wind power station for making famous Ketel One vodka.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

A floating cat sanctuary on an Amsterdam canal.