Cruise ships are increasingly becoming small floating cities. When measuring cruise ships, gross tonnage (GT) is used instead of passenger capacity, length, or draft in meters. The term "ton" originated from the number of wine barrels or tons a sailing ship could carry. A GT is equivalent to 100 English cubic feet or 2.83 m3, approximately the size of a telephone booth. Therefore, ships are measured rather than weighed and are referred to as having a "GT," "tonnage," or "measurement of x GT." These are the top ten largest cruise ships in the world. Brought to you by Tourism Review.