The tour goes south towards Mt. Herdubreid, stopping by in Herdubreidarlindir, and then further south-southwest towards the stratovolcano crater-lake Askja. The last volcanic eruption was in 1961, but a tremendous eruption was in 1875, creating the smaller milk-colored volcanic lake Viti (Hell) which is still warm from the geothermal heat under, so you can take a bath! This nicely made video by an Italian couple gives a good picture of what the area north of Vatnajokull looks like. A video from YouTube, 9:34 minutes, created by pixie0172.