Helepolis (, English: "Taker of Cities") was an ancient siege engine. It was used in the unsuccessful siege of Rhodes in 305 BC. It is based on an earlier, smaller design used against Salamis in 306 BC. The name was taken from the Greek ""ελείν πόλεις"", meaning destroyer of "cities". Vitruvius, Plutarch, and in the Athenaeus Mechanicus. It was the largest and most powerful siege tower ever built.