The remains of Crystal Palace Great Exhibition of 1851.

An incarceration museum on the spot of possibly the oldest prison in England.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

Remnants of a Victorian garden feature sitting in public woodland.

Catacombs turned marketplace.

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

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

A special shop catering to the needs of things that go bump in the night, and also helps kids become writers.

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

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

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

A student driver's nightmare.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

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

While comics are the main attraction at this megastore, the second floor plays host to an exhibit fit for a museum.

This museum offers an actual time machine back through Colorado's past.

Once a mortuary that held the remains of Buffalo Bill, this Denver hotspot is now a death-fixated restaurant.

This modern antique shop is a museum for 1980's Saturday morning cartoon culture.

A technicolor place of worship for Elevationists.

A hidden garden of stones engraved with scriptures, a Joseph Smith Sphinx, all carved by one man.

Inside this museum, the history of the Walt Disney Family empire is on full display.

One of the last remnants of the city's Chinese nightclub scene is now a dive bar selling killer mai tais.

This print shop boasts one of the largest pinball arcades in San Francisco.

This residential door allows San Francisco muggles a glimpse at the wizarding world.