Engineering from Above

Explore a massive defensive wall surrounding a historic Colombian city and see how a series of eerie metal structures protected the English coast during WW II; then visit a vast underground refuge in Turkey designed to protect tens of thousands.

An aerial view of an ancient temple engineered to survive the ravages of time, a cathedral rising from the heart of Barcelona, and a remote, cliffside shrine that seemingly defies the laws of gravity.

Revealed from above; The Pantheon, one of ancient Rome's enduring and enigmatic feats of engineering; in Panama, a continent-crossing canal that almost never was; and in a remote valley in Spain a supersized cross built to memorialize the dead of a brutal civil war.

Revealed from above; a big bridge spanning a gigantic gorge in France; a record-breaking outdoor elevator in China; and the world's longest tunnel carving its way deep beneath the Alps.