The AT-AT (All Terrain Armored Transport) is a large, four-legged walking robot ("walker") introduced in The Empire Strikes Back and also appearing in Return of the Jedi.
Dialog in National Public Radio's adaptation of The Empire Strikes Back states that AT-ATs "look like animals"; the character goes on to describe the vehicles as carrying "extremely heavy armor and armaments". The AT-AT, designed to favor "fear over function", is manned by two men to drive the vehicle and can carry up to five speeder bikes and 40 Imperial stormtroopers. The walkers themselves carry two blasters and two laser cannons. Manufactured by Kuat Drive Yards, Expanded Universe sources describe the AT-AT as being either 15 metres (49 ft) or 22.5 metres (74 ft) tall. Their armor is resistant to most standard blaster weapons; however, the "neck" column of the walker holds no such invulnerability and, if shot, can cause the entire walker to be destroyed.
The AT-AT is the primary assault vehicle during the Battle of Hoth, first depicted in The Empire Strikes Back. In the film, the AT-ATs are responsible for destroying the shield generator protecting the Rebel headquarters, taking out many soldiers, vehicles, and installations in the process. One walker is destroyed when a Rebel Alliance Snowspeeder wraps a tow cable around the legs, causing its collapse. Another AT-AT is destroyed by Luke Skywalker, who damages critical systems underneath the walker with his lightsaber and a grenade. The AT-AT also makes a cameo appearance in Return of the Jedi, where one guards a landing platform on Endor.