Royal Caribbean International is offering a cruise that may not be out of this world, but it is certainly round this world.

The Royal Caribbean Group brand has begun taking reservations for an Ultimate World Cruise that plans to cover all seven continents in 274 days aboard the 2,490-berth Serenade of the Seas (built 2002).

This will not be the first time that Royal Caribbean or other cruise providers have held global trips, but it will certainly be the longest ever by far.