Though somewhat small by modern standards, the Titanic was gigantic for its time. There were 10 decks. The top one was the boat deck, the next eight decks were A to G, and then there was the orlop ...

The PromenadeLights from a submersible penetrate the rusted ruin of Titanic’s first-class promenade, once as inviting as a similar deck on the Olympic (right). Before the Titanic sank ...