Dettifoss is a waterfall in Vatnajökull National Park in Northeast Iceland, and is reputed to be the second most powerful waterfall in Europe after the Rhine Falls. Dettifoss is situated on the Jökulsá á Fjöllum river, which flows from the Vatnajökull glacier and collects water from a large area in Northeast Iceland. The sediment-rich runoff colours the water a greyish white. The falls are 100 metres wide and have a drop of 44 metres down to the canyon Jökulsárgljúfur.