A human mole, lower right, burrows his way through the wall in an attempt to penetrate the city. Tunneling under or through a wall was a safer, but technically more difficult, method of breaching a fortified city’s defenses. This detail from a slab in the throne room of the Northwest Palace of Ashurnasirpal II (883–859 B.C.), at Nimrud, also shows two other soldiers, armed with spears and curved shields, mounting a scaling ladder amid falling bodies, upper left and right center. In the tower, upper right, one defender holds a small convex shield, the other, a stone ready to be hurled down upon the scaling attackers.