The seawater playground of gilded-era San Francisco burned to the ground in 1966.

This London marker celebrates the spot where the world-famous English band was founded.

A network of bells in the pubs and restaurants around Westminster alerts politicians when it's time to cast their votes.

These docile dragons are ideal inhabitants for the conservatory greenhouses.

A relic of Victorian grandeur hides beneath a busy South London road.

A plaque marks the underground site of one of London's "lost rivers."

Shiny Brutalist box commemorates a pioneer of electricity and houses a railway transformer.

Art Deco and “Wrenaissance” mash-up, this recently restored royal residence has been home to kings and comes with secret monkey passages included.

This elaborate Byzantine-style building was designed for a not-so-pretty purpose.

The cedar tree in Highgate Cemetery earned its title by accident.

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

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

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

Repository for more than 22 million pickled specimens.

The remains of Crystal Palace Great Exhibition of 1851.

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

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

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.

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

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

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

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