This document discusses different types and sizes of cruise ships. It identifies several styles of cruise lines including mass-market lines like Carnival Cruises and Norwegian, premium lines, luxury cruises, and masted sailing ships. It also outlines ship sizes based on gross registered tonnage and passenger capacity, ranging from very small ships under 10,000 GRT to megaships over 70,000 GRT carrying over 2,000 passengers. Finally, it lists the 10 largest cruise ships in the world by passenger capacity, ranging from Royal Caribbean's Allure of the Seas carrying 5,400 passengers to Cunard's Queen Mary 2 carrying 3,873 passengers.