The royal funeral chariots of Thailand were used since the Ayutthaya period, but they were destroyed when Ayutthaya was completely sacked in 1767. New funeral chariots were commissioned during the reign of King Rama Iat the beginning of the Rattanakosin period. They include, among other smaller accompanying vehicles, the two main chariots which have been used to transport the bodies of kings of the Chakri Dynasty, the Maha Phichai Ratcharot, built in 1795, and Vejayanta Ratcharot, built in 1799. The chariots, built of teak and ornately carved, gilded and decorated, have a tall, tiered design symbolizing Mount Meru surrounded by devata and nāga. The chariots are topped with a butsabok which houses the royal funerary urn containing the royal body. Despite the term used, the "chariots" have four wheels and are pulled by hundreds of men. The Maha Phichai Ratcharot was used for the funeral procession of King Bhumibol Adulyadej in October 2017. It was drawn by 216 men. The 13.7 tonne chariot is 18 metres long, 11.2 metres high, and 4.8 metres wide. It has been used 25 times, most recently in 2012 for the cremation of Princess Bejaratana Rajasuda, the late king's cousin. The royal chariots are housed in the Bangkok National Museum and undergo restoration when they are needed for royal funerals. Following custom, The doorsill of the exhibition hall and a section of the museum wall are demolished and a path is laid each time the chariots need to be brought outside. Then the structures are rebuilt and the path removed after the ceremony ends, signifying that their future use is not anticipated. An additional chariot, the Rajarot Puen Yai, is used only for the cremations of the King in his constitutional duty as Head of the Royal Thai Armed Forces as the urn carrying his remains is carried in procession around the royal crematorium at the Sanam LuangRoyal Plaza thrice before the cremation services begin. The carriage is modeled on those used in the royal and state funerals in the United Kingdom, and was restored yet again in 2017.