Public access to clean drinking water was an instant hit among the masses.

Two plaques commemorate the site of Shakespeare's first theatre.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

The lab where the scientist made his groundbreaking discoveries is preserved on the basement floor of the Faraday Museum.

Where condemned pirates met their grisly end at the gallows on the River Thames.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

A Roman spa buried deep beneath the City of London.

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

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

The remains of Crystal Palace Great Exhibition of 1851.

A network of concealed passageways lies within a busy London Underground station.

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 pub with prison cells in the cellar and a "spy room" on the second floor.

The anatomical-pathological collection of a man who changed surgery.

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

Catacombs turned marketplace.

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

A student driver's nightmare.

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.

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