On Deck 2, extending fore and aft from the Grand Lobby is the other main corridor. If you go forward you'll get to the lifts and stairs of Stairway B, and get to the beginning of the "Maritime Quest". If you go aft you'll pass the Golden Lion pub on the starboard side, the photo gallery on the port side, past Stairway C and finish up at the lower entrance to the Britannia Restaurant.
The Maritime Quest is a series of information boards scattered throughout the ship mainly covering life in the golden age of cruising, and a bit about the Queen Mary 2. There's a couple of hundred of them and they take hours to read. Before the refit last year you could get an audio guide from the Purser's Office but when I asked about it they said they weren't doing it anymore.
Lifts of Stairway B, and the Maritime Quest first information board
Australian mural near Stairway B
Looking from the Grand Lobby aft towards the lower Britannia Restaurant
Looking towards the lower entrance of the Britannia Restaurant
Postbox outside the Golden Lion Pub