Helepolis

The Helepolis was a massive siege tower designed by Polyidus of Thessaly in the 300s BC. The seige tower was 130 feet wide and 60 feet tall, clad in iron plates, with an armament of several catapults, most firing 30 kg projectiles, though there was one four 60 kg catapults and two 180 kg catapults on the lower floors. The tower also had four light ballistae on top. The tower was powered by 200 men operating a crank and over 3000 men pushing from behind. The vehicle was capable of forward, reverse, and sideways movement, but could not "steer". The Helepolis met its downfall when it got stuck in a patch of mud at the Siege of Rhodes in 305 BC. The Rhodians won the siege and sold the iron plates and catapults in the Helepolis off after the battle and used the profits the construct the Colossus of Rhodes, a bronze statue that was later listed as one of the Seven Wonders of the Ancient World.