A discarded movie prop that was the original monolith for "2001: A Space Odyssey."

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

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

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

The bridge is a secret gallery of discarded gum that has been transformed into miniature masterpieces.

Buried for centuries, this hidden cellar is all that remains of London's medieval Whitefriars Monastery.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

One part local history, 99 parts gruesome haunted house.

The broken skateboards that became a poignant memorial to a murdered skater.

Colorful murals by Jean Cocteau hide within this peaceful London sanctuary.

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

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

London's smallest police station is barely the size of a phone booth.

The bronze uniforms commemorate the vital role of women during World War II.

Pop culture has helped to keep this iconic British building from being destroyed.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

The rose garden in Regent's Park where Pongo and Perdita met for the first time in Disney's "101 Dalmatians."

London's amazing modernist public square that never was.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

The grave of the legendary "Bonzo" can often be seen covered in cymbals and drumsticks.

The house in the middle of the motorway.

The longest cutting on the M62 contains some surprises—though it's best to leave the motorway to appreciate them.

These 90-year-old murals of local kings, Vikings, and outlaws hide in plain sight in a beautifully baroque shopping arcade.