Angkor (Khmer: អង្គរ, "Holy City") is a region of Cambodia that served as the seat of the Khmer Empire, which flourished from approximately the 9th to 15th centuries. The word Angkor is derived from the Sanskrit nagara (नगर), meaning "city". The Angkorian period began in AD 802, when the Khmer Hindu monarch Jayavarman II declared himself a "universal monarch" and "god-king", until 1351, when Angkor first fell under Ayutthayan suzerainty, to 1431, when Ayutthaya put down a rebellion and sacked the Khmer capital, causing its population to migrate south to Longvek.
The ruins of Angkor are located amid forests and farmland to the north of the Great Lake (Tonlé Sap) and south of the Kulen Hills, near modern-day Siem Reap city (13°24′N, 103°51′E), in Siem Reap Province. The temples of the Angkor area number over one thousand, ranging in scale from nondescript piles of brick rubble scattered through rice fields to the magnificent Angkor Wat, said to be the world's largest single religious monument. Many of the temples at Angkor have been restored, and together, they comprise the most significant site of Khmer architecture. Visitor numbers approach two million annually, and the entire expanse, including Angkor Wat and Angkor Thom is collectively protected as a UNESCO World Heritage Site.
Angkor Wat (Khmer: អង្គរវត្ត) is the largest Hindu temple complex and the largest religious monument in the world. The temple was built by the Khmer King Suryavarman II in the early 12th century in Yasodharapura (Khmer: យសោធរបុរៈ, present-day Angkor), the capital of the Khmer Empire, as his state temple and eventual mausoleum. Breaking from the Shaivism tradition of previous kings, Angkor Wat was instead dedicated to Vishnu. As the best-preserved temple at the site, it is the only one to have remained a significant religious centre since its foundation – first Hindu, then Buddhist. The temple is at the top of the high classical style of Khmer architecture. It has become a symbol of Cambodia, appearing on its national flag, and it is the country's prime attraction for visitors.
Angkor Wat combines two basic plans of Khmer temple architecture: the temple mountain and the later galleried temple, based on early Dravidian Architecture, with key features such as the Jagati. It is designed to represent Mount Meru, home of the devas in Hindu mythology: within a moat and an outer wall 3.6 kilometres (2.2 mi) long are three rectangular galleries, each raised above the next. At the centre of the temple stands a quincunx of towers. Unlike most Angkorian temples, Angkor Wat is oriented to the west; scholars are divided as to the significance of this. The temple is admired for the grandeur and harmony of the architecture, its extensive bas-reliefs, and for the numerous devatas adorning its walls.