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

Among Europe’s most spectacular Ice Age painted caves still accessible today.

From a 1930s bathing beach to a 1970s dumping ground, this stretch of Buenos Aires is now its largest and wildest reserve.

Cross towering trestles and tunnels on a historic canyon rail trail.

London’s first road overpass is so old that it was originally built for horse-drawn carriages.

This boat represents the promise of undiscovered territory, a dream of hope, and progress and freedom for Iceland.

This historic bridge connects Whidbey Island to Fidalgo Island across whirlpool-filled waters.

A historic highway suspension bridge on the old Fraser River highway has been preserved for non-motorized traffic.

Honoring the adaptive athlete's Marathon of Hope.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

This massive library holds what was once the largest book collection in the world.

The site of an ancient city pillar that was lost and rediscovered.

This mysteriously shaped boulder may have been used for human sacrifice in ancient times.

This grand hydraulic installation has provided water for townspeople since the Middle Ages.

An ancient Phoenician citadel once stood at the site where Queen Dido first landed, according to legend.

An ancient burial ground believed to have been used for ritual sacrifice.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

A superb Paleo-Christian baptismal pool is preserved among the ruins of ancient Sufetula.

A charming Amazigh village carved into a mountaintop.

The largest salt lake in the Sahara is mysteriously alluring.

The best-preserved Roman small town in North Africa.

A 15th-century granary that played the role of futuristic slave quarters in the world of 'Star Wars.'

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