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

This coffee shop lies hidden beneath a historic church.

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

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.

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.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.