This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

This curious, round temple is the oldest still-standing marble building in Rome.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

The final resting place of the poets Shelley and Keats.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

An alchemist's "magic door" stands in the middle of a Roman park.

Model Trains and Much More in Hamburg.

Executed in 1401, Exhumed in 1878, Stolen in 2010.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

One part local history, 99 parts gruesome haunted house.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

Eighty million natural history specimens call this gargantuan museum home.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

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

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

The approximate spot where the last Grand Master of the Knights Templar was put to death.

In this Parisian garden's grotesque former life as a zoo it fed exotic animals to the bourgeois and put humans on exhibit.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

How did a French journalist’s grave become the sexiest statue in the cemetery?