Sikkim is a land of dramatic contours. Rugged mountains, deep valleys and dense forests consort with raging rivers, lakes and waterfalls to create a visual feast. The state has the steepest rise in altitude over the shortest distance and has within its 7,096 sq. kms the entire climatic range, from tropical to temperate to alpine.

Rivers
Sikkim has two main rivers, the Teesta and the Rangeet, both of which are formed at high altitudes and flow in a generally southern direction till they converge at the confluence near Melli. The source of the Teesta is the pristine Cho Lhamu Lake in North Sikkim. From here the river travels downwards to meet Zemu Chu just above Lachen village and the Lhachung Chu at Chungthang. At Mangan, the river is joined by the Talung Chu as it continues its journey down, finally widening at Singtam to become double its width. Further down at Melli, the Teesta merges with the river Rangeet which is born of the Rathong glacier in West Sikkim before entering the plains of North Bengal and eventually joining Brahmaputra in Bangladesh.