For 10 points, identify this place, the primary fortress of Rohan and the scene of the climactic battle in The Two Towers.
During the Long Winter, this place served as the base and last refuge of a king who secretly entered enemy camps to kill foes with his bare hands. A hill of dead soldiers called the Death Down was formed after a battle at this place by a force of Huorns. A force of infantry relieved a siege of this place under Erkenbrand, who had earlier lost a key ford over the Isen. The horn of a ruler with the epithet (*) "Hammerhand" was kept in this place. This fortress was breached by an explosion in its drainage culvert and was nearly lost to an army of Dunlendings, Orcs, and Uruk-hai before Gandalf arrived with an army at dawn. For 10 points, identify this place, the primary fortress of Rohan and the scene of the climactic battle in The Two Towers.
During the Long Winter, this place served as the base and last refuge of a king who secretly entered enemy camps to kill foes with his bare hands.
Hornburg (accept Helm's Deep since the movies use the name of the valley it's in as the name of the fortress)