17. Savarona — 124 metres / 408 feet. We begin with a beautiful 1937 yacht made for American heiress Emily Roebling Cadwalader. It was bought by Turkey as a Presidential yacht, and in 1989 had a $35 million (£24 million) refurbishment.
16. Katara — 124 metres / 408 feet. A superyacht with a mysterious origin, the Katara apparently has a Qatari flag when it docks. Boat International thinks it belongs to the new young emir Sheikh Tamim bin Hamad al-Thani.
15. Maryah — 125 metres / 410 feet. Built in Poland in 1991 as a Russian research vessel, the yacht was redesigned in the UK for luxury, and can accommodate? 54 passengers.
14. Octopus — 126 metres / 414 feet. Owned by Microsoft co-founder Paul Allen, this massive yacht spends most of its time moored in Antibes, France, and even has a helicopter landing pad.
13. Al Mirqab — 133 metres / 437 feet. The Al Mirqab won the Motor Yacht of the Year award at the World Superyacht Awards in 2009 and reportedly has a top speed of 20 knots.
12. Serene — 134 metres / 439 feet. Built in 2011 for a Russain owner under a veil of secrecy, little is known about the Serene, except that she's the largest yacht ever launched into Italian waters where it was built.
11. Rising Sun — 138 metres / 453 feet. Originally built for Oracle CEO Larry Ellison, he eventually sold it to music mogul David Geffen in 2010.
10. Al Salamah — 139 metres / 457 feet. The Al Salmah had a codename of "Mipos" during construction, short for "Mission Possible." It's one of the many superyachts once owned by Saudi royalty on this list, in this instance Prince Sultan bin Abdul Aziz.
9. Ocean Victory — 140 metres / 459 feet. Another entry with a super-secret background (notice a trend?) the Ocean Victory supposedly has seven decks, six swimming pools and a "floodable garage" at its base.
8. Yas — 141 metres / 463 feet. With a facade that wouldn't be out of place on Star Trek, the Yas was launched in 2011 by holding company Abu Dhabi MAR using repurposed steel from a Dutch navy vessel. Its owner is unknown.
7. El Horriya — 146 metres / 478 feet. The boat was built in 1865 for an Ottoman governor. It was the world's largest yacht for 119 years before the next entry took the title.
6. Prince Abdulaziz — 147 metres / 482 feet. The Royal Yacht of Saudi Arabia's King Abdullah. It reportedly cost $184 million (£126 million) in 1984. An interior lobby is said to be based on the design of the Titanic.
5. Topaz — 147 metres / 483 feet. Constructed in Berlin, the Topaz was launched in 2012 and cost $527 million (£361 million) to build. It has a gym, cinema, jacuzzi and conference room.
4. Al Saïd — 155 metres / 509 feet. Built in 2006 for the Sultan Qaboos of Oman, the Al Saïd has the highest water displacement of any on the list at 15,850 tonnes. It also has a concert hall that can accommodate? a 50-strong orchestra.
3. Dubai — 162 metres / 532 feet. This gigantic yacht was commissioned by Prince Jefri of Brunei in 1996 and is currently owned by Sheikh Mohammed bin Rashid Al Maktoum. Apart from the usual luxuries, the Dubai also has a 21 metre wide atrium to impress the 24 capacity guests staying overnight.
2. Eclipse — 162.5 metres / 533 feet. The world's second-biggest superyacht was launched in 2009 at a reported cost of $500 million (£342 million) for Russian billionaire and Chelsea FC owner Roman Abramovich. It takes an annual voyage to the Caribbean to take passengers back to Abramovich's home in St Barth's.
1. Azzam — 180 metres / 591 feet. Built by German company Lürssen Yachts, who made six of the top ten entries, the world's biggest private superyacth has an unknown owner, though many speculate it belongs to the royal family of Abu Dhabi. It cost an estimated $600 million (£411 million) and supposedly houses a submarine with its own missile defence system.
Indian real estate rebounds as institutional investment touches a three-year high of $2.5 billion in three months
Why are so many people dying at Hathras, Uttar Pradesh?
10 getaways near Jaipur to explore this monsoon
