It's meant to be a ship of dreams, an $800 million luxury liner where elegant passengers glide across ballroom floors, sample caviar or soak up the sun on the high seas.

But the ship was the scene of a horrifying accident on Saturday, when a gangway full of shipworkers and their families collapsed, killing at least 13 of them and injuring dozens of others.

The tragedy befell what had been promoted as the mother of all oceanliners even before its maiden voyage, scheduled for January from Britain to Ft. Lauderdale, Fla.

The Queen Mary 2 (searchis the world's largest passenger ship at 1,138 feet long and 238 feet high — as tall as a 21-story building. Seen from afar, the ship looks like a massive floating apartment complex, its hull stretching into the distance.

Calling the ship extravagant is an understatement. It features a planetarium, 22 elevators and the world's biggest floating library. It is chock full of restaurants, bars and sports facilities.

Just before the ship's first test run on the open water in September, officials gave reporters a tour of the still-unfinished innards. While much of the inside was still under construction, the ship's winding hallways and sprawling spaces for theaters and restaurants hinted at the opulence that would greet passengers.

The welcoming party on Saturday was for the thousands of workers involved in the building of the ship. The project was announced in 1998, and some 800 companies — most French — have been involved in construction. The keel was laid in July 2002.

The ship was built by Alstom Marine's Chantiers de l'Atlantique for the British ship operator Cunard Line, which is owned by Carnival Corp.

As its name implies, the Queen Mary 2 comes from a pedigree of luxury liners. The Queen Elizabeth 2 (search— whose trans-Atlantic route will be taken over by the new ship in April — was built in 1967; the original Queen Mary was launched in 1934 and now is a luxury hotel in Long Beach, California.

The Queen Mary 2's 2,600 passengers will choose from six restaurants, 14 bars and clubs, a library, a theater, pools, a disco and a casino. The 1,310 cabins include duplexes with private gymnasiums and penthouses with butler service.

Such elegance will come at a price. In France, tickets will run from just over $1,150 to more than $34,500, with tickets for the maiden voyage costing even more.

Prices vary among countries; in the United States, tickets for a six-day trans-Atlantic trip start at $1,499.

The project had suffered from periodic labor problems.

Some 300 Indian workers went on strike for 20 days in March to demand more money and better living conditions. Then 92 Romanian workers putting together the air conditioning went on strike in August, claiming they hadn't been paid for two months.

The strife subsided in September, when Alstom broke the contract with the company that hired the workers.