Situated between India and China, Southeast Asia has been the birthplace of several cultures, some of which rank among the world’s greatest civilizations. Among the Indianized kingdoms which sprang up in Southeast Asia before the Common era, is the great Khmer civilization and its capital, Angkor, in modern day Cambodia. The advent of Indians in Southeast Asia has hardly a parallel in history. In view of the ethnic affinities between the prehistoric races of India and those of Suvarnabhumi, contact between the two regions may well go back to the remotest antiquity. Most of the countries of Southeast Asia came under the cultural and religious influence of India. This region was broadly referred to by ancient Indians as Suvarnabhumi (the Land of Gold) or Suvarnadvipa (the Island of Gold). Vedic Indians must have charted Java, Yawadvip, thousands of years ago because Yawadvip is mentioned in India's earliest epic, the Ramayana. The Ramayana reveals some knowledge of the eastern regions beyond seas; for instance Sugriva dispatched his men to Yavadvipa, the island of Java, in search of Sita.

Southeast Asia was often called by many British, French and Indian scholars as Farther India, Greater India, L’Inde Exterieure, and the Hinduized or Indianized States. The various states established in this region can therefore be called Indianized kingdoms. Invasion nor proselystism was by no means the main factor in the process of Indianization which took place in the Indian Archipelago. International trade was very important. Angkor Wat indeed deserves to play the leading part not only because of its exceptional artistic and architectural achievements but also on account of the hydrological, agricultural and ecological problems solved there.

Angkor is located at the foot of Mount Kulen, a large natural water-tower from where many rivers flow down. But water was an irregular resource and the surplus had to be stored for use in the dry season. The Angkorian kings understood this and chose to build barays. These were large artificial reservoirs supplied by rainfall and diverted rivers. They were well thought out: instead of digging into the ground, people raised dykes to hold water. Water would enter through the north dyke and would later be released to irrigate rice fields. The amazing scale of such a construction, and the amount of labor (about 10,000 man-years) necessary to dig and pile up the reservoir walls, can hardly be put into adequate words.

Angkor Wat is often hailed as one of the most extraordinary architectural creations ever built, with its intricate bas-reliefs, strange acoustics and magnificent soaring towers. Angkor Wat, originally named Vrah Vishnulok - the sacred abode of Lord Vishnu, is the largest temple in the world. It was built by King Suryavarman II in the 12th century. The Sanskrit Nagara (capital) was modified by the Cambodian tongue to Nokor and then to Angkor. The word Angkor is derived from the Sanskrit word 'nagara' meaning 'holy city'. Vatika is Sanskrit word for temple. "The city which is a temple," Angkor Wat is a majestic monument, the world's largest religious construction in stone, and an architectural masterpiece. The Khmers adhered to the Indian belief that a temple must be built according to a mathematical system in order for it to function in harmony with the universe. Distances between certain architectural elements of the temple reflect numbers related to Indian mythology and cosmology. The sheer size of the place leaves visitors in awe.