Some of these features are Iceland's numerous mountains, volcanoes, hot springs, rivers, small lakes, waterfalls, glaciers, and geysers. The word geyser is, in fact, derived from Geysir, the name of a particularly famous geyser on the southern side of the island. Glaciers cover approximately 11% of the island and the largest, Vatnajökull, is up to 1 km thick and, by far, the largest glacier in Europe.