Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

A focal point of the Cuban government, this city square features one of the most iconic images in the country.

A colorful narrow alley in Cuba is full of street art and sculptures made of found objects.

In terms of history and architecture, this is one of the most remarkable cemeteries in the world.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

Sweden's "good old days" painstakingly re-created in a model village.

This city park was once a lookout point for George Washington’s army during the Battle of Brooklyn in 1776.

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

Artists and musicians now rule over this former rail station.

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

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

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

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

London's old-school healing garden.

The curios of pharmacist and collector Henry Wellcome.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

Eighty million natural history specimens call this gargantuan museum home.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

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

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