The superyacht Breakthrough, also known as Project 821, has made waves as the world's first fuel-cell-powered vessel powered by liquid hydrogen. After completing sea trials near Amsterdam, this $645 million marvel boasts an array of eco-friendly features and luxurious amenities. Storing hydrogen at a bone-chilling -423.4 degrees Fahrenheit, the yacht operates silently, free from traditional diesel engines' noise and fumes. With storage tanks capable of holding up to 543 kWh of energy, Breakthrough can run on hydrogen alone for an entire week. For long journeys without hydrogen availability, the yacht switches to ABB pod drives powered by MTU generators running on HVO biofuel, reducing emissions significantly. Despite Bill Gates not taking ownership, the yacht's features include a semi-submerged Neptune lounge, a cinema, a library, and a 27-foot contraflow pool, providing a unique experience for guests. The vessel's design showcases opulent interiors, including an atrium, floor-to-ceiling windows, and a fully equipped hospital. With townhouse-style living spread over four levels and various entertainment options like a games room and a basketball court, Breakthrough stands as a testament to luxury and innovation. While Gates' vision and climate advocacy drove this project, the yacht now awaits a potential buyer to experience its unparalleled blend of luxury and sustainability in the high seas.