Called the Golden Falls, in English, this is one of the most spectacular waterfalls I've ever seen. Part of Iceland's famous Golden Circle tour, Gullfoss falls is not to be missed. The Hvítá river drops 32 metres into a crevice in the earth, dumping between 80 and 140 m³/s of water over the edge.
One of the strange things about Gullfoss is you can't see it until you are standing above it; the river seems to vanish into the earth. Hiking down the steps to stand beside the waterfall, is well worth it, even though you eventually have to climb back up!