The remains of Crystal Palace Great Exhibition of 1851.

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

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

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

London's smallest police station is barely the size of a phone booth.

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

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Eighty million natural history specimens call this gargantuan museum home.

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

Remnants of a Victorian garden feature sitting in public woodland.

Catacombs turned marketplace.

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

Hear the quietest sound from across the dome.

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

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

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

Rebuilt remains of a temple to Roman god Mithras.

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

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

A student driver's nightmare.

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

One part local history, 99 parts gruesome haunted house.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

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