Just Off R'lyeh Way...

Although you might think that the picture below would be a good approximation of the Lighthouse of Cthulhu, it's actually on the southeastern shore of Lake Michigan, and represents what happens when wind-blown water forms icicles on the lighthouses at St. Joseph North Pier.

Some more pictures of the fantastic shapes the combination of wind, water and freezing temperatures create around the lighthouses can be found here.

(H/T Leah Libresco)