A storied line with roots that go back to the 1800s, this brand is perhaps best known for its 2,695-passenger flagship, Queen Mary 2. QM2 lives up to its billing as a true ocean liner with frequent transatlantic service between Southampton, England, and New York. Cunard fans love the line’s relatively formal vibe (including nightly dress codes) and other nods to ocean-liner tradition, including afternoon tea and evenings with ballroom dancing.