Archimedes played a major part in defending his natal city of Syracuse against a protracted Roman siege, as the designer of a host of weapons and machines to repulse the attackers. These fall into three main categories: a) cranes (or 'claws') that lifted enemy ships out of the water and dashed them against the rocks, b) catapults of every size and description that hurled bolts and stones varying distances, and c) the mirrors that focused sunlight on the ships and set them alight. This latter invention has become legendary, and much has been written about whether such a thing could in fact have been possible in the time of Archimedes. Most experts, and particularly foreign experts, were persuaded that the construction of such a system was a myth, despite the weight of literary evidence supporting the story, until engineer Ioannis Sakkas succeeded in demonstrating that it was indeed possible. Sakkas used 70 copper-plated glass lenses, with diameters ranging from 1.70 to 0.70 metres, and his experiment was carried out at the Palaska Training Centre on the island of Salamina on November 6, 1973. Sakkas placed his 70 lenses in a circle, and succeeded in focusing the sun's rays on a small boat, built in the same way as Roman craft and equipped with the same sort of materials, lying 55 metres away. In less than three minutes the boat was ablaze. Sakkas' experiment was reported around the world, and caused quite a stir. Three previous tests had also produced satisfactory results, and together they confirmed that Archimedes did indeed set fire to Roman ships. While we do not know the full effect of this conflagration, the psychological impact on the enemy must have been terrible. That, of course, is why his feat acquired the status of a legend and is still talked about to this day.