Many naturalised citizens came originally from Tibet and India. In the higher reaches of the kingdom and in some isolated valleys, hill tribes assuming Bhutanese nationality thrive on the land. Some, like those from Merak and Sakteng in the east and Laya in the north, have no contact with Western civilization and trade only in bartered goods. The Buddhist faith has played and continues to play a fundamental role in the cultural, ethical and sociological development of Bhutan and its people. Throughout Bhutan, stupas and chortens line the roadside commemorating a place where Guru Rimpoche or another Shabdrung may have stopped to meditate.
Prayer flags are even more common.
Fluttering on long poles, they maintain constant communication with the heavens. Bhutan is the only country in the world to retain the tantric form of Mahayana Buddhism as its official religion.