In the thousand years leading up to the Renaissance, developments in the construction and design of defensive fortifications changed warfare. As new tactics, weapons, and siege techniques were created to breach them, fortifications were modified to maintain their effectiveness. Along with walls, moats, and drawbridges, soldiers used measures such as machicolations—openings between a wall and a parapet through which stones and boiling water could be hurled—and killing fields, which were what? Discuss
Source: The Free Dictionary