The largest cruise ship ever built cost $1 billion — and it just set sail (RCL)

REUTERS/Stephane Mahe

Royal Caribbean took delivery of its newest ship on Sunday. Harmony of the Seas is the third ship in Royal Caribbean's Oasis class — Oasis of the Seas and Allure of the Seas entered service in 2009 and 2010, respectively. At 1,188 feet long and with a gross tonnage of 226,963 , the billion-dollar Harmony of the Seas is the largest cruise ship ever built. 

Harmony took the title of world's largest cruise ship from its sister vessel, Allure of the Seas. 

Thousands gathered to watch Harmony of the Seas sail out of STX Europe's shipyard in St. Nazaire, France for the first time on its way to Southampton, England. 

At 1,188 feet-long, Harmony of the Seas is roughly the same length as five Boeing 747s placed end-to-end.

It's powered by three, 25,000-horsepower and three 18,600-hp Wärtsilä diesel generators. They drive three electric Azipod thrusters.

Source.

Here are two of the Azipods.