Wadi Mujib, known from the Bible as River Arnon, is a river in Jordan which enters the Dead Sea at 410 metres (1,350 ft) below sea level. The Mujib Reserve of Wadi Mujib is located in the mountainous landscape to the east of the Dead Sea, approximately 90 kilometres (56 mi) south of Amman. A 220-square-kilometre (85 sq mi) reserve was created in 1987 by the Royal Society for the Conservation of Nature and is regionally and internationally important, particularly for the bird life that the reserve supports. It extends to the Kerak and Madaba mountains to the north and south, reaching 900 metres (3,000 ft) above sea level in some places. This 1,300-metre (4,300 ft) variation in elevation, combined with the valley's year round water flow from seven tributaries, means that Wadi Mujib enjoys a magnificent biodiversity that is still being explored and documented today.