An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

The steepest classic funicular in the world glides along a dizzying incline.

A replica of the steam engine that hauled Queen Victoria's Royal Train is on display at Windsor.

A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

Hidden in plain sight, this creepy sculpture watches from above.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

An architectural oddity hides in plain sight on this iconic London bridge.

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

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

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

The Tudor-style cottage in the middle of the square is not quite what it seems.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

A unique tribute to the millions of animals who served and died for the British military.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

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

London's amazing modernist public square that never was.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

Explore this medieval cathedral by trying to spot all the malevolent monsters hiding in its beautifully colored windows.

One of a series of no-purpose kinetic artworks by Swiss sculptor Jean Tinguely.

A particularly disconcerting tribute to Irish martyrs.

The 19th-century pharmacy (now a used bookstore) was featured in James Joyce’s "Ulysses," and has changed very little to this day.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.