this cave in the Vatnajokull glacier is called the anaconda, it's one of the can that can be "safely" visited during the 2018-2019 winter season.
If you decide to visit, it's highly recommenced to take a guide,
and if you can afford a private tour, it's going to be much better for photographers.
When we were on site, already the half of the cave had collapsed.
Tthe remaining part was still very impressive, with all of these shades of blue and black ice and the shapes made by the water.