Skeiðará, one of the biggest glacial rivers of Iceland, ­coming from the eastern side of the glacier Skeiðar­ár­jökull, ­usually difficult to cope with in summertime. Big floods often occur in this river, originating in the crater valley of Gríms­vötn in Vatnajökull. In 1934, for instance, the river reached a width of 9 km and a water volume of 64,000 m3/sec. A bridge was built on Skeiðará in 1974, nearly 1,000 m long and the longest in Iceland, the last link in the national Highway 1.