This is not just used in Northern Europe it is sometimes used on American maps to indicate places of interests when there is already a heavy amount of key symbols used. This is a great read and its no surprise Susan Kare referenced a international symbol dictionary, a mark of a true designer using a recognizable and readable symbol for a very important command, a true genius. If you swap out historic with place of interest to "copy" it makes a lot more sense. I wish people would take this care in designing symbols today, I've seen some freakish ones as of late on mobile phones, and especially touch devices. Have we forgotten a touch button is still a command button?