The Eurialo Castle is a jewel of Greek defense military engineering. It stands just a few kilometers west of the city centre, on a scenic place from which approaching foes could be seen from afar. Although today, due to various building projects, the landscape is not what it once was, when Eighteenth and Nineteenth century travelers wrote of its famed beauty.
The name "Eurialo" comes from The Greek word "Eurvelos" which means "broad nail", roughly describing. Originally created by Dionysius the Elder to defend Syracuse from Carthaginian invasion, it was constructed at the point at which the city walls converged. It took six years to build.
Though it underwent alterations over the centuries, its strength and brilliant design to which, it is said, Archimedes contributed, was such that it was never taken in battle.
In the following centuries, the Eurialo Castle was altered first by the Romans, and later by the Byzantines which, to protect themselves from the Arabs, made significant changes to the castle's structure, taking materials from the inside to further fortify the outside, turning it into an even greater fortress on a quadrangular plan.
Both its position and its many defense mechanisms are so impressive even by today's standards that it is easy to see why it remained such an effective stronghold in the past.
Archimedes had as enemies the Carthaginians, and knew of their formidable methods of warfare. One of these was the use of "mines" made of "Greek Fire", a lethal mix of brimstone and palm oil, which when lit didn't extinguish and, put into tunnels dug beneath city walls, caused it to collapse. So Archimedes, to combat the destruction of Syracuse, had complicated tunnels dug all around the city, to divert the path of this "mines".
The ferocity and type of warfare favored by an enemy, often determined the nature of defense. For the Romans, their barbarian enemies and style of war was limited to sticks, stones and physical energy, so the Roman Aurelian Walls, were elementary in comparison to those created by the Greeks in earlier times.
The Eurialo Castle had three fosse dug around it, with a drawbridge that did not lead directly into the castle, but to a triangular bastion. Only after conquering this bastion could an enemy hope to enter the fortress, built on a trapezium plan, and also equipped with tanks, so that in case of a siege, the inhabitants had water supplies.
The element of surprise was by no means absent at this point, as the only door to the castle was well hidden by a series of ingenious architectures: passages and underground galleries connecting every part of the castle.
The army then was able to communicate quickly and mobilize defenses, in case the enemies overcame all the other difficulties and proved to be a threat to the inhabitants.