The city was protected by a strong, tall wall and the attackers were forced to use siege towers to try and climb over it. Siege towers were wooden structures that could be moved up to a defender's walls to allow the attackers to climb over them. While some were designed to be rolled up on land, Demetrius used a giant tower mounted on top of six ships lashed together to make his attack. This tower, though, was turned over and smashed when a storm suddenly approached, causing the battle to be won by the Rhodians.