It's hard to overlook a volcanic caldera (unless it's under ice)
After a recent jökulhlaup (a flood of meltwater released from a glacier), scientists in Iceland suspected that one of their smaller icecaps might have a volcano or geothermal area under it, one that hadn't been discovered before. So they decided to find out.
A new cauldron confirmed
This article describes the image from Landsat 8 that indicated the location of the caldera. I grabbed that image and it is shown below. The arrow points to the newly-described caldera.
New caldera found on Iceland glacier
According to this article, they sent an expedition to the icecap to confirm that it was indeed a previously unknown, under-ice volcanic caldera.
Now, it's unlikely that it actually erupted; more likely, geothermal heat melted enough water to cause the jökulhlaup. But it's still interesting that a feature like this had lain undiscovered until now.
Here's the icecap, Hofsjökull, from a viewpoint closer than space.