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

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

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

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

An unusual round church in London with a Templar past.

Amsterdam's former hotspot for public executions and dissections.

Amsterdam's Red Light District leaves little to the imagination.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

The ruined doorway is a portal to the building's turbulent and torturous past.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

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

150 or so scrounged-up lamps, chandeliers, and lanterns light up this alley in central Athens.

The liveliest ghost town in the state.

An overlooked monument to the celebrity gangster who helped put the sin in Sin City.

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

Large collection from the 3rd millennium BCE.

Poseidon? No one seems to know.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

Chewing gum tycoon's memorial lies perched over wife's botanical gardens on Santa Catalina Island.

Elevated freight railway turned wildly successful urban park.

Furniture tries to escape an abandoned building in San Francisco.

Race through the maze, get your name on the sign.