Núpsá – Djúpádalur, 75 km, 8 days

This trek is described by Dieter Graser (refer to the links section). It is not a marked trail, but a truly wild enterprise. The trek brings you from the volcano Laki, that caused a worldwide famine in the 18th century by the emission of improbable amounts of sulfur dioxide, to the ice lake Grænalón. Next, the trek crosses an offshoot of the giant glacier Vatnajökull and ends in the fairytale valley of Skaftafell.

Crossing rivers of meltwater glacial ice makes this trek dangerous. Also, the crossing of the glacier Vatnajökull, even if it's only a small protrusion, is demanding and tricky. No regular walk, but a rather extreme mountain tour. One week you're on your own, carrying tent, food, everything.

This walk, and Dieter's story about it, is a good illustration of the diversity of hiking options that Iceland offers: something for everyone.