Fjaðrárgljúfur is a magnificent and massive canyon, about 100 meters deep and about two kilometres long. The bedrock in Fjaðrárgljúfur is mostly palagonite from cold periods of the Ice Age and is thought to be about two million years old. Today Fjaðrá is often rather low in water and therefore hikers can safely walk inside the canyon. However, wading is necessary fairly often. Deep in the canyon there are waterfalls. Most people choose to walk along a walking path up on the canyon’s edge while simultaneously enjoying the view above the canyon.