If you've flown from the far corners of the earth to be in Iceland, you're going to want to be in the type of place indicative of the country in its natural, glacial glory. Askja is as close to that Iceland in your head as you're going to get without having to wander off with merely the North Star as your guide. A group of volcanic calderas situated in the Dyngjufjöll mountains at the center of the country, Askja is an epic slice of Icelandic landscape often paired with a 4-WD tour of nearby Lake Mývatn.
At times inaccessible due to flooded rivers, you'll be self-driving if you're lucky between June and October via F88 and F105, otherwise it's jeep tour or nothing at all. Our advice? Don't go with "nothing at all" if you've got half a chance, even if you have to pay upward of 30,000 ISK (about $240 USD). It's a worthy conclusion to an awe-inspiring drive through lava fields and an otherworldly landscape often likened to the moon's serene and brutal beauty from the Icelandic ring-road. If the weather is right, you'll just have to end with a short trek to Askja's crater (called Viti, or "Hell") with a swim in the pool within.
If you've got some time, stick around at the nearby campgrounds in Dreki and give this incredible tundra a bit more of your time. There are hikes through mountain canyons that aren't nearly as touristy as the bus stop that Askja can turn into during high season.