Cross the long bridge and a scene will show someone up on a ledge pulling around a dead body. Go down the path to the left until you reach a wall with a handle. Pull it open for some steps to the ledge. Once you reach it, a cutscene will follow. Kratos will have a conversation and the gate will be opened by Harpies. Before you can go through the gate, however, you'll be stuck fighting two ogres. Once they're done with, go up the long staircase and pull the switch to get inside. The doors will close behind you. Your next battle is one against wraiths. After fighting them, go up to the wall and press . Go through the passage to reach the Rings of Pandora.