Titanic was the second of three Olympic-class liners built by Harland & Wolff in Belfast for the White Star Line. White Star had decided not to try to out-run Cunard's faster ships and to out-scale them instead — more room, more comfort, more spectacle.
First class got a swimming bath, Turkish baths, a squash court, a Café Parisien and the wrought-iron and glass dome above the forward staircase. The promenade decks below were the part most passengers actually experienced, and the part most photographs show.
The ship was widely described in the press as practically unsinkable. That phrase did not come from her builders as a guarantee; it came from trade papers and was repeated until it hardened into a claim nobody had quite made.