In 1974 this beautiful and large lake, known as Mývatn was set aside as a natural conservation area. This is a place where travellers can settle in, spend a week camping, sightseeing (it's an excellent base for trips to some of the most special locations in Iceland) and relaxing, without beeing bored.
Among the numerous locations there are Dimmuborgir ('black castles'), Stóragjá ('large canyon') which has a 38 C (100 F) hot spring which you can enter via attached rope. Grjótagjá is another beautiful hot spring but its temperature has risen to almost 60 degrees Celcius (140 F) in recent years and thus is far too hot for bathing. Also the 163-metre Hverfjall which has a 1040-meter-wide crater and is a very special mountain, the hollow psuedocrater Arnarbæli ('eagle's lair') and many others.
Warning: There is a speacial "feature" of Myvatn which is the swarm of midges (the name literally means 'Midge lake') that like to socialize with travellers. So you need to protect yourself with various available means (chemicals, nets etc.) and you should not use a tent without an insect screen.
Getting to the Lake Myvatn Area: You can fly to Mývatn via Akureyri or Húsavík airports (almost daily flights from Reykjavík). You can then travel the rest of the way in a bus (or rental car if you choose) which takes less than 90 minutes from both locations. You can also go on a flight over Mývatn area out of Reykjahlíð airport (the largest community near Mývatn).