Royal Caribbean's "Icon of the Seas," billed as the world's largest cruise ship, sails from the Port of Miami on its maiden cruise on January 27, 2024 (Marco BELLO)The world's largest cruise ship, Royal Caribbean's Icon of the Seas, set sail from Miami on its maiden voyage Saturday, carrying what amounted to the population of a small city. The $2 billion Icon -- the first in Royal Caribbean's new Quantum Class of ships -- is stuffed with the latest technology and, despite its mammoth size, claims to be more eco-friendly than some smaller cruise ships. The Icon is powered by what its owners say is eco-friendly Liquefied Natural Gas (though some experts say LNG systems can leak damaging amounts of methane gas into the atmosphere). After leaving its Miami home base Saturday on its sold-out inaugural cruise -- the company says ticket demand was "unprecedented" -- the Icon will spend a week in the Caribbean before returning to Miami. At 2,000 feet long (365 meters), the Icon will be taking the title of world's largest from a Royal Caribbean stable-mate, the slightly smaller Wonder of the Seas.