Hvítserkur, Vestur-Hunavatnssysla, Iceland. By Flickr user jónr.
Ailsa Craig by Flickr user atomicjeep.
Hvítserkur reminded me of Aisla Craig, a volcanic island a few miles from Girvan on the west coast of Scotland. I’ve seen Aisla Craig from the shore and can testify to its imposing presence, and also the way its appearance changes depending on the weather and time of day.
Both these pale into insignificance next to Ball’s Pyramid, a volcanic stack in the Tasman Sea which is 562 meters in height and looks like it might be Cthulhu’s second home. Flickr has further views of this spectacular eruption but not as many as you might hope.