4. Azzam – $650 million
Lürssen Yachts is behind this luxury liner which was recently delivered to fortunate Sheikh Khalifa bin Zayed al-Nayan, President of the United Arab Emirates and Emir of Abu Dhabi for no less than $650 million. This makes it the world’s fourth most expensive luxury yacht with the makers boasting that the Azzam is "the most complex and challenging yacht that has ever been built". However, not only has the Azzam been dominating the headlines for its hefty price tag but also due to its immense size. Measuring in at 590 feet long, this floating extravagance boasts the largest private yacht in the world thus knocking the Eclipse, belonging to Russian billionaire Roman Abramovich, off the top spot. In addition, this impressive superyacht is expected to be one of the fastest reaching speeds of more than 30 knots, or 35mph. The luxury interiors were designed by French interior decorator Christophe Leoni which has been described as "sophisticated and luxurious in a turn of the century Empire style". For the moment little else is known about the Azzam. Now the only question remaining is, with the world’s billionaires constantly competing to own the largest superyacht, how long will it remain at the top? .