One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.

Light still pours into the ruins of this ancient Islamic observatory.

One of the oldest surviving bars in the United States, located at the site of the last skirmish of the American Revolution.

This hulking behemoth is actually five interconnected towers built in the 1960s.

This everlasting lightning storm may be the world's largest generator of ozone.