Bhutan has relied on its geographic isolation to protect itself from outside cultural influences. A sparsely populated country bordered by India to the south and China to the north, Bhutan has long maintained a policy of strict isolationism, both culturally and economically, with the goal of preserving its cultural heritage and independence. Only in the last decades of the 20th century were foreigners allowed to visit the country, and only then in limited numbers. In this way, Bhutan has successfully preserved many aspects of a culture which dates directly back to the mid-17th century. Bhutanese culture derives from ancient Tibetan culture. Dzongkha and Sharchop, the principal Bhutanese languages, are closely related to Tibetan, and Bhutanese monks read and write the ancient variant of the Tibetan language known as chhokey. Bhutanese are physically similar to the Tibetans but history does not record when they crossed over the Himalayas and settled in the south-draining valleys of Bhutan.
Bhutanese society is centered on the practice of Tantric Buddhism. Religious beliefs are evidenced in all aspects of life. Prayer flags flutter on hillsides offering up prayers to benefit all nearby sentient beings. Houses each fly a small white flag on the roof indicating the owner has made his offering payments to appease the local god. Each valley or district is dominated by a huge Dzong, or high-walled fortresses, which serves the religious and administrative center of the district.