Launched in 2013 at a reported cost of $500 million, Azzam heads Boat International's Top 101 list at 180 meters (590 feet) in length.
2. Eclipse —
The plaything of Chelsea FC owner Roman Abramovich, Eclipse measures 162.5 meters (533 feet).
3. Dubai —
Eclipse is only half a meter longer than this vessel owned by Sheikh Maktoum, the ruler of Dubai.
Ross Land/Getty Images Europe/Getty Images for DAGOC
4. Dilbar —
Formerly known as Project Omar, Dilbar was launched this year for Russian billionaire Alisher Usmanov. Measuring 156 meters (511 feet) in length, it has the largest gross tonnage -- the measure of internal volume -- at 15,917 GT, according to Boat International.
5. Al Said —
Owned by the Sultan of Oman, Al Said was the second longest when launched in 2007, measuring 155 meters (508.53 feet).
6. Topaz —
Launched in 2012, the 147-meter (482-foot) Topaz is one of several vessels on the list built by German firm Lurssen.
7. Prince Abdulaziz —
The 147-meter (482-foot) Saudi-owned Prince Abdulaziz was the world's longest superyacht for over two decades following its launch in the mid-1980s.
10. Ocean Victory —
Russian billionaire Viktor Rashnikov's Ocean Victory (140 meters/459 feet) rounds out the top 10 after El Mahroussa and Yas.
Coming soon ... —
At 141 meters (462 feet) long, Dream Symphony will be the world's largest yacht to be powered by sail alone when it launches.
