Once a more cooperative partnership, ties between the North Atlantic Treaty Organization and Moscow have deteriorated sharply, today resembling the tense standoff of the Cold War. NATO leaders view Russia as a direct security threat, but repeated warnings and condemnations from the Alliance have so far had little effect on the Kremlin.
So, how has a previously constructive relationship between NATO and Russia turned so fractious? Click through this gallery and find out more about why Russia fell out with NATO.