Bangladesh, located in the Eastern part of South Asia, straddles the Tropic of Cancer and is enclosed by India with the exception of a short South-eastern frontier with Myanmar (formerly Burma). The Bay of Bengal lies to the South. The most significant feature of the landscape is the rivers, which have moulded not only their environment but also the way the people live. The landmass is deltaic comprising mainly the delta of three rivers: the Ganges, the Brahmaputra and the Maghna, with a network of numerous canals. The land is mostly flat alluvial plain with some hills in the South-east. Flooding of the land is a major problem. Two-thirds of the land are arable and 16 percent is covered with forests. The climate is sub-tropical and is dominated by the seasonally reversing monsoons. Winters are cool and dry, summers are hot and humid. The subtropical climate has made the country luxuriant in vegetation.