Helepolis is the Greek name for a movable siege tower.
Model of a Helepolis siege tower, Thessaloniki Science Center and Technology Museum
Naval helepolis. Two quinqueremes having a helepolis on their decks.
A siege tower or breaching tower is a specialized siege engine, constructed to protect assailants and ladders while approaching the defensive walls of a fortification. The tower was often rectangular
Helepolis
…Helepolis (Greek: ἑλέπολις, meaning: "Taker of Cities") is the Greek name for a movable siege tower. The most famous was that invented by Polyidus of Thessaly, and improved by Demetrius I of Macedon and Epimachus of Athens, for the Siege of Rhodes…
Assyrian attack on a town with archers and a wheeled battering ram; Neo-Assyrian relief, North-West Palace of Nimrud (room B, panel 18); 865–860 BC
The remains of the Roman siege-ramp at Masada
Medieval English siege tower
A vehicle used by GIGN featuring a mechanical assault ladder mounted on its roof, essentially a modern version of a siege tower