- Cannon Making
- Mechanical Clock
From earliest times walls defended cities, but gunpowder cannon made all kinds of walls and towers obsolete. To design and build defenses for cities proof against cannon required a new skill: military engineering. The applications of this are Bastions to defend against land attack and Battlements against attack from the sea.
Jericho was defended by a stone wall by 6000 BC. Variations on a theme of high vertical walls and towers defended cities throughout the ancient world, providing elevated platforms for missile fire and protection from enemy weapons. Gunpowder artillery changed all this. No stone wall or tower could withstand repeated strikes by missiles weighing hundred of pounds propelled by gunpowder explosions. In the late 15th century in Italy, military engineers and architects began devising methods of reinforcing or redesigning existing stone walls, towers, or castles so they could withstand the new artillery. The answer, arrived at through trial and error, was to lower the walls, cover them with earth to absorb impacts, and dig wide trenches or dry moats to keep the enemy guns at a distance. These Ramparts were later expanded into advanced geometric positions called Bastions from which your own artillery could flank and counter enemy assaults. The premier designer, builder, and taker of fortresses and fortified towns was Sebastien Le Prestre de Vauban, whose "Vauban Fortifications" defended the borders and towns of France from 1660 to 1760 and remained formidable into the twentieth century: the citadel of Hue, a Vauban style fortification, withstood assaults by modern weapons in 1968 during the Tet Offensive in Vietnam.