Nepal’s landmass of 141,181 km2 (54,510 sq mi) occupies the central part of the Himalayas between the Palearctic and Indomalaya ecozones. Altitude ranges from 67 m (220 ft) above sea level in the south-eastern Terai to 8,848 m (29,029 ft) at Sagarmatha within a short horizontal span. This extreme altitudinal gradient has resulted in 11 bio-climatic zones ranging from lower tropical below 500 m (1,600 ft) to nival above 5,000 m (16,000 ft) in the High Himalaya, encompassing nine terrestrial ecoregions with 36 vegetation types.