Altough not fantastic diving, Sweden has curious divesites to offer: its 3000km long coastline offers world-class wreck diving! Sweden has an interesting history with its period of being a great power between 1611-1721 where a number of vessels foundered at sea (Ricksnyckeln, Riksäpplet, Vasa, among others). Nowadays there are between 9,000 and 10,000 registered and documented shipwrecks of both wooden and steel vessel types. Researchers estimate that there are a total of 40,000 known wreck positions in the Baltic Sea. Because Sweden doesn't having any woodworm to destroy the wrecks as well as low-salt levels of the water in the Baltic Sea, this makes perfect preservation conditions for the wrecks, and therefore excellent opportunity to dive straight into history!
See that Sweeden also offers the opportunity to ice diving, a big challange for any diver!