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

This one has sailed five times as far as Sir Francis Drake's famous ship.

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

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

Ship-sized kinetic sculptural fantasy.

This luxury shopping lane has been protected by its own tiny police force for over a century.

A community of artists and entrepreneurs seeks a simpler life on London's waterways.

Charles Babbage's proto-computer, painstakingly brought to life.

The largest of London's subterranean rivers and once a mad, bad center of London life.

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

Eighty million natural history specimens call this gargantuan museum home.

Catacombs turned marketplace.

A hands-off space for graffiti artists to hone and display their skills.

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

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

A church of bones, decorated with 40,000 human skeletons.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

Bullet holes in the church wall are a reminder of the violence that followed the assassination of a high-ranking Nazi officer.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

A mocking tribute to the past and modern leadership of Prague.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

A Jenga-style cylindrical tower of books that appears to go on forever.