The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

Go inside to really appreciate this 500-year-old technological masterpiece.

Two stone columns flank the grand Venice square, but there were supposed to be three.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A semi-scholarly approach to sex.

Elevated freight railway turned wildly successful urban park.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

The unsettling remnants of a torn down movie set lies nearby the ruined location of the actual Płaszów Labor Camp.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

The celebrated eyesore created by starry-eyed sweethearts.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

Real bones which are said to have belonged to a Polish dragon.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Macabre astrological automaton clock dating to the late 1400s.

Go surfing on this urban wave, "hacked" by local surfers.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”