The lunar-like volcanic craters, bubbling mud-flats and stark lava fields of Iceland's Lake Myvatn National Park are the spectacular setting for the Myvatn Baths (www.steam.is), which have opened near the northern city of Akureyri as a new and less crowded alternative to the famous Blue Lagoon near Reykjavik. The natural spa has geothermally heated pools and two steam baths with therapeutic, mineralised water from a deep underground fissure. Entrance is £7 per adult; children go free.