The new Sun Princess is the biggest ever from cruise line Princess.
It can carry 4300 passengers and 1600 crew.
It has more than 30 restaurants and bars, thousands of staterooms and suites and countless pools and hot tubs.
On a recent sailing, 9Travel got a little behind-the-scenes sneak peek into how it all works.
Read through to see the secrets!
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The Bridge is where the ship is commanded from.
We met Captain Paolo Arrigo, who is from Italy.
He showed us his seat, which offers a great view out in front.
The seat next to him is for a local pilot, who hops on board at each port to safely negotiate the ship for the last part of the journey, he said.
You can often see tiny pilot boats alongside the massive cruise ships for this reason.
Captain Arrigo showed us some of the fancy tech.
But binoculars are also still also used to look out to sea for hazards such as other ships or whales.
There isn't a big wheel to steer the ship like you might imagine from movies, but a small joystick, as well as something known as pods or Azipods.
They're a kind of propulsion unit to make the ship move.
The Captain also confirmed an interesting superstition.
He has a bottle containing the first water to splash on the Sun Princess, which he keeps in his office.
It's traditionally gifted to captains as part of an age-old tradition.
The bridge also has 'wings' that stick out, so the side of the ship can be seen whenever it's needed, such as when it's in port.
Away from passenger areas, there's one main large crew corridor, known as I-95.
It's named after a major highway in Florida, the world's biggest cruise hub.
There are over 250 chefs working on Sun Princess to keep the hungry passengers - and crew - fed.
That includes more than 1000 cruisers who choose to eat nightly in the main dining room, Horizons.
It's a near-24-hour operation.
Some other onboard eateries have their own kitchens.
At Umai Teppanyaki Japanese, chefs even cook in front of you.
A stash of salad gets prepared in advance, then is storied in a huge fridge ready to be served to passengers that night.
Chefs on board are each responsible for a certain item every night.
Photos of what each main dining room dish should look like are displayed in the huge galley.
A good supply of soft drinks - plus booze - is loaded on at the start of each cruise.
Ships even have massive fridges for fresh flowers, and a big laundry to handle the massive amount of washing and ironing.
Meanwhile, the ship makes its own water from the sea, using desalination and reverse osmosis.
"Our whole focus is to lower our environmental footprint," VP of Communications, Vicki Johnson told us.
There was also plenty of beer ready in this on-board stash.
Each bar on the ship makes different cocktails, so a lot of ingredients are needed.
Ever wondered happens to your leftovers?
They go into one of these giant digesters and are whittled down to a liquid waste.
There are five on the ship, with bits diners have not eaten arriving in big containers and constantly fed in.
We can confirm it didn't smell too nice.
As much as possible is recycled, with all the rubbish taken to a central area and carefully sorted.
The ship is also the first Princess vessel to run on Liquified Natural Gas, which the company says is better for the environment.
Where possible they use shore power in port, rather than running the engines.
Cardboard packaging and paper is pulverised into these briquettes, which is then used to fuel the machine that creates them.
Glass is crushed and offloaded to make sand traps on golf courses.
Some buses and trains in Alaska also run off Princess's old oil, which is made into biodiesel fuel.
There are strict rules on what ships can release into the ocean - and where.
The crew has a huge mess area to eat and hang out, where all the workers dining together.
On many ships, officers and crew eat separately.
The big buffet in the crew mess looked like it would be pretty tasty before a long shift.
The writer travelled as a guest of Princess Cruises.