Catacombs turned marketplace.

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

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

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

A student driver's nightmare.

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

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

A mysterious artist-run cabinet of curiosities and library.

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

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

Hear the quietest sound from across the dome.

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

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

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

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

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

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

An unusual round church in London with a Templar past.

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

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

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

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

Since 1874, this macabre collection has developed into a museum devoted to Scotland Yard's mementos of dastardly deeds.