The wreck of a submarine found off Sweden's coast was probably a Tsarist-era Russian vessel that collided with a ship about a century ago, the country's military has announced.
"We are most likely talking about the Russian Som-class submarine – nicknamed Catfish – which sank after a collision with a Swedish vessel in 1916 during the first world war and before the Russian Revolution," the Swedish armed forces said.
http://www.theguardian.com/world/2015/jul/28/sweden-submarine-wreck-tsarist-russian-som-catfish (http://www.theguardian.com/world/2015/jul/28/sweden-submarine-wreck-tsarist-russian-som-catfish)