Once a massive dungeon spanning four levels, Atal’Hakkar was shaken to its very foundation by the Cataclysm and the lower floors crumbled: rendering them inaccessible and blocking off large portions of the ruins to adventurers.
However, while that story may be true in the World of Warcraft cannon, the real truth is just that the developers wanted to make The Sunken Temple less confusing to navigate, and blocked off the lower levels during the Cataclysm revamp.
And while that may be sad news for fans of the original dungeon, never fear! Developers are much less destructive than dragons, and where Deathwing leveled the lower floors; the devs merely moved the instance portal into the upstairs hallway, preventing players from going downstairs. But an especially daring outlaw rogue can bypass the instance portal in the method detailed above and venture forth to explore the original temple for themselves!
Upon reaching the bottom of the stairs behind the portal, we’re greeted by the original entrance room for the dungeon. A large rectangular chamber with 4 sets of stairs leading in various directions, and a fifth set blocked by an invisible wall that once held the entrance portal for the dungeon.
Continuing ever further into the depths leads us to the great pool at the base of the dungeon. Players would need to light 6 beacons on the balconies shown above in the correct order to summon the Idol of Hakkar, who they would fight in the center pit.
Directly above the pool, you can see the underside of the small grate in the main chamber which looks down into the lower levels. This grate is the only glimpse players in the new dungeon normally get of the original structure.
Heading back to the top levels via a series of staircases, we come to the upper floor. A circular hallway which runs around the upper edge of the Cataclysm dungeon, with various stairwells leading down onto six now-inaccessible platforms which overlook the main chamber.
The long abandoned lower levels of the Sunken Temple provide us with a fascinating look at how much of an area can be blocked off by simply making a few minor adjustments.