If the headline is a bit puzzling, the concept is a bit amazing. MSC Cruises, having decided that some of its ships were smaller than optimal, decided to stretch them out. It's now halfway through a 4-ship refit that involves slicing the liners in half and welding in a new 79-foot section of ship, pre-built at the shipyard.
Italy's Fincanteri shipbuilders is doing the work, with the amazing goal of getting each ship (latest is MSC Sinfonia) back into service 10 weeks after arriving at the drydock. That means a lot of coordination, a lot of night work, and having the new section ready to go before the ship arrives.
Once the new section is welded in, the next step is reconnecting all the pipes and wires, and furnishing the added 195 staterooms (along with more restaurant, deck and bar space). More pictures on USA Today, but here's a You Tube video posted by MSC: