One of the world's largest collections of pathological specimens.

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

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

A cluttered and astounding collection of antiquities and curiosities.

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

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

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

The curios of pharmacist and collector Henry Wellcome.

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

An unusual round church in London with a Templar past.

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

Rebuilt remains of a temple to Roman god Mithras.

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

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.

Hidden beneath the streets of London is a secret subway that only carried mail.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

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

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

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

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

This coffee shop lies hidden beneath a historic church.

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

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