light blue in model B); and one with a diamond-shaped keystone (the Gothic arch, model C). Flying buttresses act the same way ancient Roman columns did, countering the horizontal force of the arch.

Rome's ancient Arch of Constantine was hit by lightning during a heavy storm, causing some fragments to fall off, an official said Wednesday. "All the fragments were recovered and made safe ...

Ancient American geological formation, the Double Arch, suddenly collapsed on Wednesday, the National Parks Service said. Also known as the Toilet Bowl and the Hole in the Roof, the natural ...