At the foot of Mt Námafjall, Hverir appears: one of the country's largest fumarole fields, covered with mud cauldrons resulting from hydrothermal activity. Bubbling grey mud, yellow splashes of sulphur, red glints of oxydised earth... in the middle of white fumaroles, pulsations of the earth put on an unreal spectacle. Do not stray from the waymarked areas, as the ground is unstable, and avoid exposing yourself to the fumaroles for too long.