The oldest private residence in New York City.

The last water-powered beam pumping engine in Britain.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

The attic of a four-century-old canal house hides a clandestine church.

The oldest living tree in Manhattan comes shrouded in sinister legend.

An artist's cute bronze subway sculptures belie his violent artistic past.

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

The star-studded street honors the city's most notable Brummies.

This eye-catching roundabout sculpture commemorates one of England's best World War II-era "shadow factories."

This ornate English estates "Prodigy House" still bears the cannonball marks of civil war.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Metro station with a claim to rock n' roll fame.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A fascinating insight into daily life in the Eastern Bloc.

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

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

Eighty million natural history specimens call this gargantuan museum home.

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

A kaleidoscopic warehouse-maze of handmade neon signs.