Selvallavatn
Just getting out of the badlands, and we spied this thing that looked like a river. But the guide explained, this was actually a lake! And great for fishing, apparently.
It probably used to be kind of ovalish shaped, until a lava flow pushed its way from the northwest and just took over 75% of its area. Such is life in Iceland. But look it up on a relief map, it’s pretty amazing.