Pics of 'underground city' in Finland's capital surface amid Russian attack fears

Pictures of Finnish capital Helsinki's 'underground city' with hundreds of bunkers have surfaced online, amid fears of Russian retaliation against Finland's bid to join NATO. The underground city can reportedly shelter 900,000 people, a third more than Helsinki's population of 600,000 people, for months in case of a war. The hidden city has a swimming pool and a hockey rink.