Six of the 10 most expensive yachts in the world are owned by billionaires from the United Arab Emirates, Qatar, and Oman. But the title of the world’s most expensive yacht goes to Russian businessman Roman Abramovich. His $1-billion, 536-foot-long yacht, Eclipse, launched in 2010, had added the distinction of being the world’s longest super-yacht, until last year.

It has now been surpassed in length by Azzam , the 590-foot-long yacht owned by Sheikh Khalifa bin Zayed al-Nayan, President of the United Arab Emirates and the ruler of Abu Dhabi. Azzam sailed into second place on a new Wealth-X list of the world’s most expensive yachts, with a $600-million price tag.

The third spot goes to Topaz , a 482-foot-long yacht valued at $520 million and owned by Mansour Bin Zayed Al Nahyan, another member of the Abu Dhabi royal family. Only one American billionaire is featured in the list — entertainment mogul David Geffen, whose yacht, Pelorus , is valued at $300 million.