Eastern South Asia is a subregion of South Asia. It includes the countries of Bangladesh, Bhutan, India (specifically East India and Northeast India), and Nepal. Geographically, it lies between the Eastern Himalayas and the Bay of Bengal. Two of the world's largest rivers, the Ganges and the Brahmaputra, flow into the sea through Eastern South Asia. The region includes the world's highest mountainous terrain and the world's largest delta, and has a climate ranging from alpine and subalpine to subtropical and tropical. Since Nepal, Bhutan, and northeast India are landlocked, the coastlines of Bangladesh and East India serve as the principal gateways to the region.