Based on wookieepedia the All Terrain Armored Transport (AT-AT) was a four-legged combat walker used by the ground forces of the Galactic Empire. With the Imperial-class Star Destroyer and the TIE fighter, it was one of the most famous symbols of the Empire's military might.
The AT-AT walker was developed for use in the Imperial Army, the ground forces of the Galactic Empire. It was the successor of the All Terrain Tactical Enforcer that saw use during the Clone Wars, although it constituted a far more imposing example of walker technology. Heavily armored and awe-inducing, the AT-AT positioned itself as the standard of Imperial firepower on the battlefield. My design is not minifigure scale, its a bit smaller than the official Lego set, but it's still big and heavy.