Angkor Thom is not a singular temple dedicated to a Hindu deity such as Angkor Wat; instead, it is the name of one of the most impressive royal cities of the Angkor Period (9th–15th centuries) and an urban planning marvel. At the height of its power, the Angkor Empire (also sometimes called the Khmer Empire) controlled much of modern day mainland Southeast Asia; however, the center of its kingdom always remained in Angkor—in what is today Siem Reap, Cambodia.
With each successive king came the building of a new royal city such as Angkor Thom. The name, Angkor Thom, translated from the Khmer language means “Great Kingdom,” alluding to the grand ambitions of its patron: King Jayavarman VII. Upon coming to the throne, Jayavarman VII quickly began the process of building a new royal city (Angkor Thom) and state temple (Bayon) in the late 12th century because he understood, like Khmer rulers before him, that the capital would serve as the political and religious center of his kingdom. However, unlike rulers past, Jayavarman VII built a city that was sacred in both its form and its symbolism.
Stone inscriptions, portrait sculptures, and an extensive building program provide modern historians with a more complete record of Jayavarman VII and his rule than most early Khmer leaders. These various archival materials describe him as a prolific patron of public works, as well as a devout Buddhist (uncommon for rulers at this time). In the Yay Hom inscription, Jayavarman VII is celebrated as the greatest of all kings, and is likened to the Buddha.
This supreme kings of kings, having acquired the knowledge by himself in the city named Jayadityapura [city of his birth], wanted to liberate those who are plunged in the ocean of unhappiness. He was like Sauddhodani (Gautama Buddha) in the city of Sakyas. 
While such descriptions of Jayavarman VII associate him with the Buddha, portrait sculptures that were distributed throughout the kingdom at the time of his reign visualize this connection. In one example, now in the collection of the National Museum of Cambodia in Phnom Penh, a nearly life-sized, stone sculpture of Jayavarman VII depicts him seated in a meditative pose with his legs crossed. His head is slightly bent, and his eyes are downcast. His hair is tightly pulled back into a discreet bun, resembling iconography associated with the Buddha (such as we see in a 9th-century sculpture from Bihar, India).
Although surviving sculptures no longer include Jayavarman VII’s arms, it is believed that they would have originally been bent at the elbows and slightly raised with their hands in anjali mudra or the gesture of reverence. He is bare chested and wears a simple sampot (a rectangular piece of cloth that can be fashioned into a skirt or shorts) from the waist down.
This austere public presentation of Jayavarman VII was intended to suggest that he was a Buddha of his era, but also to present the king as a devout and humble man of the people. To prove that his gestures were not just vanity, he built hundreds of rest houses and hospitals throughout his kingdom, some as far as modern northeast Thailand, which were intended to alleviate the pain and suffering of his citizens.  However, his most ambitious architectural project was the royal city of Angkor Thom.
Angkor Thom as a Mandala
At the symbolic center of many early Southeast Asian royal cities was the temple-palace (such as Angkor Wat) that was intended to serve as the earthly abode for the kingdom’s principle deity while on earth, and as the final resting place of its patron. However, such temple-palaces were not always located at the center of the royal city, making them largely symbolic religious centers.
The Bayon Temple in Angkor Thom is an exception as it is located in the heart of the royal city. Scholars have suggested that the city of Angkor Thom is organized as a mandala or a sacred diagram of the universe. We can see this in the layout of the city, and in the architectural and visual narratives presented there.
Buddhist mandalas can take a variety of forms such as sand or Thangka paintings, or as architectural monuments such as Borobudur in Yogyakarta, Indonesia. What they have in common are their visualization of the Buddhist cosmos, which is defined by a series of nested squares and circles that represent the continents and oceans of the universe. Mandalas are further divided into five spaces: four quadrants that represent the cardinal directions (north, east, south, west), and the center, which represents the center of the Buddhist universe.
The city of Angkor Thom is square in shape, and delineated by walls that measure 8 meters high (26 feet) and that are 3 kilometers in length (1.86 miles) on each side. The walls are built of laterite, which is readily available in Cambodia. The enclosed city measures roughly 900 hectares (2225 acres) and is further protected by a moat (baray) that encircles it. Together, the walls and moat are intended to symbolize the continents and oceans in a mandala.
To enter the city, one is required to traverse one of five bridges or causeways that lead to gates that pierce the city’s walls. The bridges and gates are located at the cardinal directions, and all but one lead directly to the Bayon Temple, which is situated at the center of Angkor Thom.
The fifth gate and bridge, located north of the East Gate, leads directly to the royal palace. It is referred to as the “Victory Gate” and would have been used by the king to depart or return to his royal residence.
This highly fortified city suggests that Jayavarman VII was concerned with protecting Angkor Thom from outside intruders. Indeed, he came to the throne during a period of turmoil, having vanquished the Khmer’s longtime enemy, the Chams, who had taken over Angkor sometime between 1177 and 1182/83.  As already noted, however, one can see that Jayavarman VII had grander ambitions for Angkor Thom, as the city was also designed as a mandala, symbolizing his royal city as heaven on earth.
Speaking to Hindu and Buddhist audiences
The five bridges that lead to Angkor Thom are identical in length, width, height and imagery. Each bridge is decorated with carved stone balustrades depicting larger than life-sized figures of gods (devata) and demons (asura). There are 54 gods on the left, and 54 demons on the right, for a total of 108 figures on each bridge.
The gods and demons are depicted in a slightly crouched position pulling on a naga (serpent). The terminus of each side of the balustrade is sculpted into a hooded seven-headed naga. It is believed that these figures depict the story of the Churning of the Ocean of Milk, a cosmogonic Hindu myth. It is not entirely clear why such an important Hindu narrative is represented at Angkor Thom, especially as Jayavarman VII was a Buddhist and the state religion at the time conformed to the king’s personal belief system. Nevertheless, people living in Angkor did not change their religious beliefs or associations because of regnal changes so it may have been prudent for Jayavarman VII to adopt a narrative that could speak to both his Hindu and Buddhist audiences. In addition, scholars have speculated that the narrative had become absorbed in Khmer culture by the late 12th and early 13th century so that its Hindu origins were not relevant. Instead, certain aspects of the Churning of the Ocean of Milk story, such as its association with Mt. Meru—the center of the Hindu, Buddhist, and Jain universes—was the focus at Angkor Thom. In the story, the gods and demons work together to release the elixir of life (amrita) by churning the cosmic ocean, using Mt. Meru as its pivot and the naga as their churning rope. At Angkor Thom, the Bayon Temple, with its many peaked face-towers, is intended to represent Mt. Meru.
This is just one hypothesis though. Others such as Paul Mus have argued that the naga causeways represent a rainbow bridge that connects the world of man to the world of gods.  Without knowing the true intent of Jayavarman VII, one can still surmise that together, the city walls, the moat that encircles Angkor Thom, the naga bridges, and the Bayon point to an ambitious planned city that maximizes political and religious symbolism.
Although Jayavarman VII was a Mahayana Buddhist, the particular beliefs and practices he ascribed to are unclear.
This is most evident in the ambiguity of the identity of the face towers that decorate the Bayon Temple and the entrance gates into Angkor Thom. The gates, identical in scale and imagery, measure 23 meters (75 feet) in height. They are topped by three towers that are carved with four faces, each facing one of the cardinal directions. There is little consensus among the scholarly community of who the faces may represent. It has been speculated that they may depict the Mahayana bodhisattva, Avalokiteshvara; the Tantric, Buddha Vajrasattva; or the Hindu deities Brahma and Shiva.  Such associations are due to a variety of reasons, including each deity’s iconography, which includes multiple faces. Nonetheless, the smiling faces on the towers look strikingly similar to the portrait sculptures of Jayavarman VII, and were likely modeled after him as the most important person in Khmer life at the time and the structure’s patron. In this way, the faces can be interpreted as representing both the king and the deity.
The ambiguity surrounding the identity of the faces reminds us that our desire to create clear and definite categories for subject matters of the past is for our own convenience. There is little doubt that the form of Mahayana Buddhism practiced and understood during the time of Jayavarman VII was informed by Hinduism and other animist and ancestor worship traditions that had been practiced in Cambodia before the 12th and 13th centuries. Acknowledging this may help to explain the inclusion of the Churning of the Ocean of Milk narrative at Angkor Thom.
World Heritage Site
Visitors to Angkor Thom today will experience the city not as its inhabitants did during the time of Jayavarman VII, nor as those who continued to utilize it well into the 17th century. The balustrades that line the causeways leading up to the city and the grand gateways are no longer gilded and painted, and the cloth banners that lined the city to greet the arrival of exalted guests no longer flitter in the wind. During the reign of Jayavarman VII, the inhabitants of the royal city of Angkor Thom included the king, the royal family, military and political officials and their families, as well as priests and other service people. The royal palace, and other structures that made the city habitable and comfortable were made of wood, and no longer survive. All that remains of the royal palace complex that date from the time of Jayavarman VII are stone foundations for viewing terraces as well as the laterite steps leading down to the royal baths.  However, descriptions by the Chinese diplomat, Zhou Daguan, who visited Angkor from 1296–97, and published in his book The Customs of Cambodia, recalls the splendor of life in the royal city.
Each time he [King Indravarman III] came out all his soldiers were gathered in front of him, with people bearing banners, musicians and drummers following behind him. One contingent was made of three to five hundred women of the palace. They wore clothes with a floral design and flowers in their coiled-up hair, and carried huge candles, alight even though it was daylight. 
Although Zhou Daguan’s description postdates Jayavarman VII’s reign, it provides us with insight into the pageantry of royal life as well as knowledge that Angkor Thom continued to be used as the royal city by successive kings.
Today, Angkor Thom makes up part of the Angkor Archaeological Park, which in 1992 became a UNESCO World Heritage Site. In the same year, Angkor was inscribed in the World Heritage List in Danger because many of the temples in the park were at high risk of collapse as well as looting.  In recent years, museums, auction houses. and private collectors in the United States and Europe have returned sculptures taken from various Angkor period temples; however, many sculptures, including those from the naga balustrade of the gods and demons at Angkor Thom, remain in museums abroad. The sculptures that continue to line the bridges leading up to Angkor Thom are a combination of original works and copies that have replaced the looted or damaged works. While archeological work and conservation is on-going at Angkor, and the illegal looting of cultural material has greatly reduced over the past five decades, there is still much work to be done to understand and preserve the great monuments of Cambodia’s heritage.
Notes: Claude Jacques, “The historical development of Khmer culture from the death of Suryavarman II to the 16th century,” in Bayon: New Perspectives, ed. Joyce Clark (Bangkok: River Books, 2007), p. 34.  Helen Ibbitson Jessup, Art and Architecture of Cambodia (London: Thames & Hudson World of Art, 2004), p. 162.  Jacques, p. 37.  David Chandler, A History of Cambodia, Fourth Edition (New York: Routledge, 2009), p. 78.  Joyce Clark, ed., Bayon: New Perspectives (Bangkok: Riverbooks, 2007).  For a reconstruction of Angkor Thom visit the Smithsonian Channel’s Youtube video “The Mystery of Angkor’s Palace.”  Zhou Daguan, Cambodia: The Land and Its People (ed. and tr. Peter Harris) (Chiang Mai: Silkworm Books, 2007).  “Angkor,” UNESCO
Coedes, George. Angkor: An Introduction (Hong Kong: Oxford University Press, 1963).
Freeman, Micheal and Claude Jacques. Ancient Angkor (Bangkok, Thailand: Riverbooks, 2003).
Jessup, Helen Ibbitson. Art and Architecture of Cambodia (New York: Thames & Hudson World of Art, 2004).
Rooney, Dawn. Angkor, fourth ed. (Hong Kong: Airphoto International Ltd., 2002).
Zhou Daguan, A Record of Cambodia, The Land and Its People, translated by Peter Harris.
Chiang Mai, Thailand: Silkworm Books, 2007.