One of the cornerstones of global security since the Cold War is in danger of collapsing. The Open Skies treaty allows countries to fly aircraft over each other's territories and monitor military activity. However, Russia is following the U.S. by pulling out of the pact. Will the decision make the world more dangerous? And is the pact still relevant today in a world of high-tech surveillance drones? - Subscribe to our channel: aje.io/AJSubscribe - Follow us on Twitter: twitter.com/AJEnglish - Find us on Facebook: www.facebook.com/aljazeera - Check our website: www.aljazeera.com/ #AlJazeeraEnglish #InsideStory #ColdWar