Flags of the 57 OSCE participating States outside the Hofburg Congress Center, Vienna, Austria, October 13, 2017. (USOSCE/Colin Peters)

Flags of the 57 OSCE participating States outside the Hofburg Congress Center, Vienna, Austria. (USOSCE/Colin Peters)

Flags of the 57 OSCE participating States outside the Hofburg Congress Center, Vienna, Austria, October 13, 2017. (USOSCE/Colin Peters)