Neal Stephenson: Towering spires of rock, some of which are underwater. It's surrounded by hazards to navigation that ships are forever running aground on. Some mudflats along the beaches. Lots of ice, and lots of guano deposited by seagulls. They claim that it was formerly richly forested, but all the trees had been chopped down by Englishmen. That is true of several parts of the British Isles, so that's not even particularly fictitious.