Often, if a yacht is referred to as a mega-yacht or superyacht, it's because they have been given an official designation. The world's most significant title can be claimed by two different vessels. In 2014, Azzam—a yacht owned by Sheikh Khalifa bin Zayed Al Nahyan—took home the Guinness World Record for being number one. It measures 590 feet in length and boasts a swimming pool that can accommodate 60 people on its top deck alone. However, some argue that Dilbar takes the cake with its impressive 636-foot length.