Tunnel warfare in the context of "Combat engineer"

A siege tower or breaching tower (or in the Middle Ages, a belfry) is a specialized siege engine, constructed to protect assailants and ladders while approaching the defensive walls of a fortification. The tower was often rectangular with four wheels with its height roughly equal to that of the wall or sometimes higher to allow archers or crossbowmen to stand on top of the tower and shoot arrows or quarrels into the fortification. While the towers were primarily constructed of wood and thus flammable, their builders typically incorporated whatever non-flammable coverings could be readily procured including iron and/or fresh animal skins.

Evidence for use of siege towers in Ancient Egypt and Anatolia dates to the Bronze Age. They were used extensively in warfare of the ancient Near East after the Late Bronze Age collapse, and in Egypt by Kushites from Sudan who founded the 25th dynasty. During classical antiquity they were common among Hellenistic Greek armies of the 4th century BC and later Roman armies of Europe and the Mediterranean, while also seeing use in ancient China during the Warring States Period and Han dynasty. Siege towers were of unwieldy dimensions and, like trebuchets, were therefore mostly constructed on site of the siege. Taking considerable time to construct, siege towers were mainly built if the defense of the opposing fortification could not be overcome by ladder assault ("escalade"), by mining, or by breaking walls or gates with tools such as battering rams.