Last year, the Royal Canadian Mint issued seven collector's coins to celebrate Superman's 75th anniversary. Looks like it's a hard habit to break, because at this year's Fan Expo in Toronto, the mint announced it was issuing four more coins with images from covers dating back to Superman's debut in 1938.

Though he's widely considered a U.S. hero, Superman has Canadian roots. Joe Shuster, who co-created Superman with Jerry Siegel, was born in Toronto.

The four coins depict Superman from the covers of the Shuster-drawn Action Comics #1 (a 10-dollar coin), Action Comics #419 drawn by Neal Adams (a 15-dollar coin), Adventures of Superman #596 drawn by Mike Wieringo (a gold 100-dollar coin), and Superman Annual #1 drawn by Kenneth Rocafort (a 20-dollar coin).

The coins are limited to a minting of 10,000 each. Prices range from about $70 Canadian for the 10-dollar coin to $751 for the gold coin.