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

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A roadway designed for a visiting monarch.

This sculpture of disembodied body parts forms a poignant memory of the horrors of World War II.

An unusual ode to the late Irish playwright, complete with a squiggly bust and coffin-shaped bench.

A 150-year-old steam locomotive crosses the southern half of the island daily.

This cannonball embedded in the side of an Edinburgh house once served a surprisingly pedestrian purpose.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

The middle finger of modernity.

Decrepit Victorian public lift is a white-knuckle ride.

These seaside shelters once enjoyed by royalty remain a part of local history.

This multicolored meandering masterpiece is Britain's longest bench.

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

Legends say that this Art Deco apartment building almost became Hitler's British headquarters.

The famous polar explorer stands outside the Royal Geographical Society's headquarters.

The arching stretch of London's longest street holds many reminders of the area's maritime past.

Originally meant to hold a statue of King William IV, this support sat empty for years. Today, it hosts a rotating cast of public artwork.

The world's largest collection of ship figureheads includes figures from legends and history alike, from Sir Lancelot to Abraham Lincoln.

At the top of the hour, figures of the London department store's two co-founders emerge and bow to each other.

This underpass became an unlikely piece of cinematic history after its appearance in 'A Clockwork Orange.'

Formerly known as Saville Theatre, this mid-20th-century entertainment hub includes an ornate frieze.

The medieval woodcut-style artwork chronicles life in medieval London.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

Its collection includes a broad array of social, geographic, graphic design, and political history.