Large pneumatic bags designed to contain blasts from improvised explosive devices are finding a peaceful application in Egypt, propping the crumbling interior of the nation’s oldest pyramid. When inflated, an array of the 1.5-meter-tall bags will allow workers safely to stabilize the fractured interior roof of the subterranean burial chamber, itself buried under the ancient stone heap that forms the Pyramid of Djoser, south of Cairo. Built nearly 4,900 years ago in the reign of Djoser, the first king of the Third dynasty, the structure is the world’s oldest major stone monument, according to Zahi Hawass, secretary general of Egypt’s
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.