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Iceland has a national tradition called Jólabókaflóð, or the "Christmas Book Flood." Families give each other books on Christmas Eve and spend the holiday reading together. Iceland publishes an astonishing five titles per every 1,000 residents, and most books in the country are sold from late September to early November. This tradition began during World War II, when strict currency restrictions limited the amount of imported giftware. Imported paper was less restricted than other products, so Icelanders often gave books as Christmas gifts.