Welcome to the world of uber-rich people owning uber-luxurious yachts. The longest of 'em all - the Azzam (meaning "Resolute") - is a private yacht built by Lürssen Yachts. Azzam spans 180 metres (590 ft) in length and was built at an astounding cost of US$605M.
Another outstanding yacht is the Eclipse, the world's second largest private yacht at 162.5 metres (533 ft 2 in). Owned by Russian billionaire Roman Abramovich, Eclipse has two helicopter pads, 24 guest cabins, two swimming pools, several hot tubs, and a disco hall. Eclipse is manned by 70 crew members and was built at a cost of around US$500M.
At third longest, is the yacht named Dubai and naturally, owned by the Ruler of Dubai, Sheikh Mohammed bin Rashid Al Maktoum, Dubai measures 162 metres (531 ft) long. Including its 88 crew members, Dubai can hold more than 115 guests and was built at a cost of US$400 million.