The Istana Nurul Iman palace(Jawi: ايستان نورول ايمان) -world's largest palace

The Istana Nurul Iman palace (Jawi: ايستان نورول ايمان) is the official residence of the Sultan of Brunei, Hassanal Bolkiah, and the seat of the Brunei government. The palace is located on a leafy, riverside sprawl of hills on the banks of the Brunei River, a few kilometers south of Bandar Seri Begawan, Brunei's capital.The name "Istana Nurul Iman" is taken from Malay Istana and Arabic Nur-ol Imaan and means Palace of the Light of Faith. It was designed by Filipino architect Leandro V. Locsin, who utilized the architectural motif of golden domes and vaulted roofs to echo Brunei's Islamic and Malay influences. The interior of the palace was designed by Khuan Chew, Design Principal of KCA International, whose other works include the Burj Al Arab in Dubai. Construction was handled by Ayala International, a Filipino construction firm, and completed in 1984 at a total cost of around $1.4 Billion USD.
Upon completion, Istana Nurul Iman, became the largest residential palace in the world and the largest single family residence ever built.

The palace contains 1,788 rooms, which includes 257 bathrooms, a banquet hall that can be expanded to accommodate up to 5,000 guests, a mosque accommodating 1,500 people. The palace also includes a 110-car garage, an air conditioned stable for the Sultan's 200 polo ponies, and 5 swimming pools. In total, Istana Nurul Iman contains 2,152,782 square feet (200,000 m²) of floorspace.

Because of its massive size, Istana Nurul Iman makes use of 564 chandeliers, 51,000 light bulbs, 44 stairwells, and 18 elevators.
The title of the "world's largest palace" is difficult to ascertain, and controversial, as different countries use their own unique standard to claim that their palace is the largest. Using various definitions, a number of palaces are claimed to be the world’s largest: Istana Nurul Iman, Buckingham Palace, Quirinal Palace, Royal Palace of Madrid, Stockholm Palace, The Forbidden City, The Palace of Versailles, The Royal Palace of Caserta, The Winter Palace, The Louvre Palace, Prague Castle, and Romania’s Palace of the Parliament.

To be considered for the Guinness World Record, the palace must have been intended for use as a royal residence, and only the combined area of the palace’s indoor floors (a measurement commonly known as floorspace) is considered. As measured by these standards, Guinness World Records currently considers Istana Nurul Iman to hold the title as the "world's largest residential palace.