The remains of Crystal Palace Great Exhibition of 1851.

Remnants of a Victorian garden feature sitting in public woodland.

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

Eighty million natural history specimens call this gargantuan museum home.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

Catacombs turned marketplace.

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

Rebuilt remains of a temple to Roman god Mithras.

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

One part local history, 99 parts gruesome haunted house.

An unusual round church in London with a Templar past.

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

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

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

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

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

Banksy gives themself artistic license with this piece of London street art.

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

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

A kaleidoscopic warehouse-maze of handmade neon signs.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

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

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