An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A stairway to heaven, or to nowhere at all.

This small collection of rare books was uniquely locked up for safe keeping.

Catacombs turned marketplace.

An abandoned tank sits in an empty London lot as a symbolic middle finger to local city planners.

A comic book store that puts the marvel back in marvellous.

Scattered throughout London are ancient remnants of the city's former bounding wall.

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

A famous burial ground with a history both grim and literary.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

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

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

This South London cemetery holds the remains of more than 15,000 people.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Hear the quietest sound from across the dome.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

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

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

A tongue-in-cheek arcade where the games are based on everyday life.

A hands-off space for graffiti artists to hone and display their skills.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A mysterious artist-run cabinet of curiosities and library.

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