One of the largest ships in the world, Oasis of the Seas makes an impression even before you board; the mega-ship looms above its counterparts. The this-can't-be-a-ship effect continues as you board; lined with eateries, shops selling designer goods and logowear, and Starbucks -- and no outside windows -- the ship's Royal Promenade can feel like a mall, rather than a cruise ship.

And yet, Oasis of the Seas has been enthusiastically embraced as one of Royal Caribbean's most beloved vessels, even more than a decade after its launch. At double occupancy, Oasis sails with 5,606 passengers, but during the busiest seasons there can be nearly 6,700 people onboard. Its onboard attractions are so popular that up to one-third of the passengers never even leave the ship in port.

So what makes Oasis of the Seas a hit for the families and active cruisers who love it? The secret is not only in the ship's neighborhoods -- which divide the vessel into manageable pieces, keep bottlenecks to a minimum and provide a dizzying amount of activities -- but also in Royal Caribbean's ability to evolve Oasis over time, sinking $165 million into the ship in 2019 as part of its Royal Amplification initiative to revitalize older ships.

The Boardwalk boasts two rock climbing walls, a carousel, the AquaTheater, the Ultimate Abyss dry slide and the impressive Playmakers Sports Bar & Arcade. The aft deck Pool and Sports Zone has the Perfect storm trio of other water slides, a kids splash park, two FlowRider surf simulators, a basketball court, a mini-golf course, a table tennis area, a teen club and a short zipline. Add in the sheer amount of shows, restaurants and bars, and you'll see that it's impossible to be bored on this ship.

Cruising on a ship this size comes with compromises. If you want to see all the shows and entertainment on offer, you must book online in advance, as the theaters are simply not big enough to hold everyone. Specialty dining reservations should be made in advance, too. If you don't like planning your cruise activities before you board or hate lines, Oasis is probably not a great choice compared to Royal Caribbean's more intimate ships.