Founded in 670, this ancient mosque is an architectural time portal.

Made famous by "Star Wars," these troglodyte homes face an uncertain future.

Buildings from the fictional planet of Tatooine still litter the Tunisian desert.

Macabre astrological automaton clock dating to the late 1400s.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

This futuristic German television spire is actually the world's largest digital clock.

The history and future of cannabis.

One of Ireland's most infamous prisons for rebels including men, women and children.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Elaborate tile work in this railway station tells the story of Portugal.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

A popular European tradition makes its way to the states on one of America's most famous bridges.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.