In Dark Souls, what is the name of the fortress filled with traps before Anor Londo?

In Dark Souls, the fortress filled with traps before Anor Londo is Sen’s Fortress.

Sen’s Fortress becomes accessible after the player rings both Bells of Awakening. Its interior is packed with swinging blades, pressure traps, boulders, narrow bridges, and serpent-men enemies. The area tests movement and observation more heavily than many earlier locations, and several hazards can kill a character even without a direct enemy attack.

The fortress serves as the route to Anor Londo, the grand city visited during the game’s middle section. At its summit, the player faces the Iron Golem, whose defeat allows the game’s gargoyles to carry the character to Anor Londo.

Players sometimes mistake Sen’s Fortress for the Duke’s Archives because both are major late-game routes associated with Anor Londo. The Archives are reached after the player acquires the Lordvessel and progress advances much further; Sen’s Fortress is the earlier gateway to the city.