The largest ship built for an Italian cruise line, Costa Concordia is a larger version of fleetmates, the identical sister ships Costa Magica and Costa Fortuna, which are in turn essentially clones of parent company Carnival Cruise Lines' Carnival Triumph. Not content to merely copy the features of sister cruise lines, Costa has pulled out all the stops with Costa Concordia. The "Samsara" spa isn't simply an ordinary spa; it's the largest spa at sea, extending over two decks and spanning 20,500 square feet.