Burning Mirrors tells the tale of Archimedes, one of antiquity's greatest engineers and mathematicians. According to legend, Archimedes repelled the Roman fleet at Syracuse by harnessing the energy of the sun:
"Afterwards, when the beams were reflected in the mirror, a fearful kindling of fire was raised in the ships, and at the distance of a bow-shot he turned them into ashes. In this way did the old man prevail over Marcellus with his weapons."The veracity of the tale has been disputed throughout history, but in 1973 a Greek scientist tried (with resounding success!) to replicate the event.
And check out these cool speculative animations of another of his inventions. Archimedes claw was used to defend the harbor at Syracuse -- to overturn the siege-ships of the city's enemies.