This 3,647-passenger vessel, christened by Her Majesty, Queen Elizabeth II in 2015, is P&O's flagship. Designed by world-class interior design experts, Britannia has a stylish palette of black, cream, and bronze with hints of blue that gives it a clean, crisp aesthetic. Passengers get their first sense of the dramatic architecture as they enter the three-deck atrium with its elegant, sweeping staircase dominated by "Star Burst" — a gorgeous art installation that's part sculpture, part chandelier.