Helepolis

The Helepolis, Greek for taker of cities, is a massive wheeled siege tower built for the Hellenistic king Demetrius I Poliorcetes during his siege of Rhodes in 305 and 304 BCE, standing many stories tall, armored on its exposed faces with iron plates to resist fire, and fitted with platforms of catapults and other siege engines that could be brought to bear as it was pushed up against the city's walls. Ancient accounts describe it as one of the largest siege engines built in the ancient world, requiring a large crew of men working internal wheels and winches to move it, but the defenders of Rhodes ultimately repelled the assault, flooding the ground in front of the walls to mire the tower and forcing Demetrius to abandon it. According to later tradition, the Rhodians sold the abandoned engine's metal and timber and used the proceeds, along with other captured Macedonian siege equipment, to help fund the construction of the Colossus of Rhodes.