File:MSMajestyOfTheSeasEdit1.JPG|350px|thumb|MS Majesty of the Seas, a cruise ship completed in 1992

A cruise ship or cruise liner is a passenger ship used for pleasure voyages, where the voyage itself and the ship's amenities are part of the experience. Cruising has become a major part of the tourism industry, with millions of passengers each year. The industry's rapid growth has seen nine or more newly built ships catering to a North American clientele added every year since 2001, as well as others servicing European clientele. Smaller markets such as the Asia-Pacific region are generally serviced by older tonnage displaced by new ships introduced into the high growth areas. Cruise ships operate mostly on routes that return passengers to their originating port. In contrast, dedicated transport oriented ocean liners do "line voyages" and typically transport passengers from one point to another, rather than on round trips. Some cruise ships also engage in longer trips which may not lead back to the same port for many months (longer round trips).

Traditionally, an ocean liner for the transoceanic trade will be built to a higher standard than a typical cruise ship, including stronger plating to withstand ocean voyages, most commonly crossing the North Atlantic. The only dedicated transatlantic ocean liner in operation as a liner, as of December 2008, was the Queen Mary 2 of the Cunard fleet. The liner Queen Mary is in service as a hotel in Long Beach, USA, the Queen Elizabeth 2 is slated for similar duty in Dubai, and the United States is currently stored in Philadelphia, USA, with long-standing plans to return it to service, although this appears increasingly unlikely given its age and condition.

Early years

The first vessel built exclusively for this purpose was the Prinzessin Victoria Luise, designed by Albert Ballin, general manager of Hamburg-America Line. The ship was completed in 1900.

The practice of cruising grew gradually out of the transatlantic crossing tradition, which never took less than four days. In the competition for passengers, ocean liners added many luxuries — the Titanic being the most famous example — such as fine dining and well-appointed staterooms.

In the late 19th century, Albert Ballin, director of the Hamburg-America Line, was the first to send his transatlantic ships out on long southern cruises during the worst of the winter season of the North Atlantic. Other companies followed suit. Some of them built specialized ships designed for easy transformation between summer crossings and winter cruising.

Jet age

With the advent of large passenger jet aircraft in the 1960s, intercontinental travellers largely switched from ships to planes, sending the ocean liner trade into a slow decline. Ocean liner services aimed at passengers ceased in 1986, with the notable exception of transatlantic crossings operated by the Cunard Line, catering to the niche market who enjoy the few days of luxury and enforced idleness that a liner voyage affords. In comparison to liner crossings, cruising voyages gained popularity; slowly at first but at an increased rate from the 1980s onwards. Initially the fledgling industry was serviced primarily by small redundant liners, and even the first purpose built cruise ships were small. This changed after the success of the SS Norway (originally the ocean liner SS France, which was converted to a cruise ship) as the Caribbean's first "super-ship". Since then the size of cruise ships has risen dramatically to become the largest passenger ships ever built.Fact: date=September 2008