Germany's Glienicke Bridge has a shady history of clandestine meetings, espionage, and spycraft.

These ruins reveal the remarkably intact layout of a Roman marketplace.

The 2,000-year-old beam is tucked within the pedestrian entrance to the old London Bridge.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

Carved fountains poignantly placed in parks and in front of special monuments.

Fantastic views and thousands of love locks.

From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

This abandoned prison castle has become an imposing gallery of graffiti art.

By day this New Orleans square is for pedestrians, but by night it is a kingdom of kittens.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

This symbolic piece of New Orleans architecture is also home to a few ghastly stories.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

The final resting place of New Orleans' most famous voodoo priestess.

An ancient octagonal weather station named for the eight Greek gods of wind.

360° views of the city plus five floors of optical illusions and hands-on science.

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

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The castle still holds traces of the abandoned Roman fort it was built atop.

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

The final resting place of many of Germany's most famous communists.

The world's longest known cave system.

Burial site more than 300 years old.

This shifting North Carolina sand dune is an odd little desert surrounded by oceanic forest life.