Link to Modern marvels: Siege machines documentary
Documentary Description
A look at siege machines that convert energy into mechanical force to go
over, under, or through fortified or fixed defenses too strong for
conventional force. These engines range from man's first long-range
missile weapon, the slingshot, to the laser cannons and
satellite-destroying robots of the 21st century. All of these machines
are designed to breach barriers--castle walls, entrenched troops, even
outer space. When the going gets tough, the tough get siege machines