Archimedes was a polymath who is widely considered the greatest mathematician of antiquity. His genius covered engineering, physics, and geometry. He famously discovered 'Archimedes' Principle'—that the buoyant force on an object is equal to the weight of the fluid it displaces—while taking a bath, allegedly running naked through the streets shouting 'Eureka!' He invented the Archimedes' Screw for moving water and developed early versions of calculus to determine the area of a circle and the volume of a sphere. During the siege of Syracuse, he designed legendary war machines, including cranes and mirrors to defend the city against the Romans.