A Keora-tree forest deep inside of the Sundarbans in Bangladesh with trees upright, rather sharp pneumatophores from superior roots visible-the roots absorb oxygen from atmosphere for surviving. The Sundarbans is the largest mangrove forest in the world. The forest covers 10,277 km2 (3,968 sq mi) of which about 6,017 km2 (2,323 sq mi) are in Bangladesh; and the Indian part of Sundarbans is estimated to be about 4,260 km2 (1,640 sq mi).