Silver Circle: 180 Litres a Second at Deildartunguhver and 1,600 m of Lava Cave

The western circuit, with every admission in the price. Deildartunguhver is the hot spring with the highest flow in Europe: 180 litres per second, at 100 °C. Standing beside that much boiling water arriving out of the ground is something the numbers do not prepare you for. Hraunfossar is a run of waterfalls spread over about 900 metres, and they do not come from a river above. The water emerges from inside the Hallmundarhraun lava field, laid down a thousand years ago by an eruption under the Langjökull glacier, which is why they are called the lava waterfalls. Barnafoss is a few metres away, and its name means the waterfall of the children: two children from a nearby farm fell from the natural stone bridge that once crossed it, and their mother had the bridge destroyed afterwards. At the Sturlureykir horse farm you can get as close to the Icelandic horses as you want, and there is rúgbrauð, the rye bread baked in the ground beside the hot spring, with coffee. Reykholt has Snorralaug, a small hot pool people have used since the twelfth century, first written about by Snorri Sturluson, who bathed in it. The Viðgelmir lava cave is the reason to book. It runs just short of 1,600 metres, one of the largest in Iceland, with lava stalactites and stalagmites and colour in the rock. The expedition inside lasts an hour and a half, and the ground around the entrance makes the scale of the eruption that built it obvious. Glanni waterfall and the woodland at Húsafell fill out the day.