The world's largest cruise ship, Royal Caribbean's Icon of the Seas, began its maiden journey on Saturday as it set sail from Port of Miami in the US.

The vessel runs nearly 1,200 feet (365 meters) from bow to stern.

The ship — which is embarking on a seven-day island-hopping tour through the tropics — was officially christened on Tuesday with help from soccer star Lionel Messi and his Inter Miami teammates.

The Icon was built over a period of 900 days at a shipyard in Turku, Finland. It comprises of 20 decks and can accommodate 7,600 passengers at maximum capacity and a crew of 2,350.

There will be 50 musicians and comedians as well as a 16-piece orchestra on board as the ship goes on its sold-out inaugural voyage.

How is the ship powered?

The $2 billion (€1.84 billion) Icon features the latest technology and, despite its gigantic size, claims to be more eco-friendly than some smaller cruise ships.

The Icon is powered by what the Royal Caribbean Group says is eco-friendly Liquefied Natural Gas (LNG).

Some experts, however, say LNG systems can leak damaging amounts of methane gas into the atmosphere.

"Icon of the Seas is the culmination of more than 50 years of dreaming, innovating and living our mission — to deliver the world's best vacation experiences responsibly," Royal Caribbean Group President and CEO Jason Liberty said in a statement earlier in the week.

 "She is the ultimate multigenerational family vacation, forever changing the status quo in family travel and fulfilling vacation dreams for all ages on board."

dvv/sri (AFP, AP)