In contrast, the few dedicated transport-oriented ocean liners that remain typically transport passengers from one point to another, rather than on round trips. Historically, shipping lines built liners for the transoceanic trade to a higher standard than that of a typical cruise ship, with higher freeboard and stronger plating to withstand rough seas and adverse conditions encountered in the open North Atlantic ocean. Compared to dedicated cruise ships, ocean liners usually have larger capacities for fuel, food, and other stores for consumption on long voyages.  Some former ocean liners, such as Marco Polo, now operate as cruise ships, although their number is diminishing.  The only dedicated transatlantic ocean liner in operation as of December 2013 was Queen Mary 2 of the Cunard Line, which features amenities of contemporary cruise ships and sees significant service on cruises.