Image Source: CIA - The World Fact Book
The Bayon at Angkor in Cambodia is a popular and richly decorated temple. The Bayon temple was built by the Buddhist King Jayavarman VII of the Khmer dynasty in around 12th Century CE as the official temple of Mahayana Buddhism in his kingdom.
The most prominent features of the Bayon temple are over 216 huge gigantic stone faces which are said to represent the faces of the king Jayavarman VII himself. However, some claim that the faces actually represent the Bodhisattva of compassion called Avalokitesvara or Lokesvara. But others regard both the hypothesis to be true. According to Angkor scholar George Coedes, Jayavarman believed in the tradition of the Khmer monarchs identifying themselves with the God – King being the same as God – Buddha and the Bodhisattva, just like how the earlier Hindu Khmer kings identified themselves with the Hindu God.
The faces in the temple were subsequently altered later when Jayavarman VIII during whose time the Khmer Empire reverted back to Hinduism and the faces were altered to represent Hindu beliefs. Then again when Theravada Buddhism became the dominant religion, the faces were altered again accordingly. And then with the decline of the Khmer empire, the temple and the faces became abandoned inside deep jungles. The temple was rediscovered inside the deep forests of Angkor only in late 19th century.
Information Source: Wikipedia & UNESCO