Designers show off plans for a $600 million superyacht, set to be the world's biggest. Its 39 luxury apartments will start at $11.2 million - and you can only buy one if you're invited.

• Plans for the world's largest yacht were revealed Monday.
• The 728 foot-long superyacht, called Somnio, is set to have 39 apartments, starting at $11.2 million.
• Bids are invite-only. Each will have a personal gym and library, as well as wine cellar access.

Plans for the world's biggest yacht were unveiled on Monday - and the boat is set to have 39 apartments across six floors, with prices starting beyond $11 million.

The 728 foot-long superyacht, called Somnio, is scheduled to launch in 2024, and has an estimated build cost of $600 million, according to a press release. The world's current biggest yacht, Azzam, is just under 600 feet long.

The luxury apartments, each with their own gym, will start at $11.2 million, and you can only offer to buy if you're invited.

The project is being led by Carl Le Souef, who is in charge of Somnio Global, which bills itself as a sustainable technology organization. Swedish design company Tillberg Design and London-based Winch Design worked together on the architecture behind the huge yacht.

The apartments will all have a kitchen, gym, library, and dining spaces both inside and outside on the terrace, per the press release. The apartments will be on six decks of the yacht.

Buyers are promised a shared wine cellar and tasting room with 10,000 bottles, as well as restaurants, bars, and a beach club with watersports.

Somnio will give buyers "the intimacy of a private yacht alongside the chance to network in a vibrant community of like-minded owners," its investors said in the unveiling on Monday, per the Financial Times.

The superyacht is already being built in Norway, and revenues from off-plan sales are helping to finance the rest of the construction, according to the FT.

"World-class medical care will also be available onboard, providing apartment owners with the highest level of safety away from pandemics and other global risks," a statement about Somnio's unveiling said, cited by The Daily Mail.