A Serbian flag is seen in front of Belgrade's Saint Sava Church as suporters of Serbian President and Russian President wait for their arrival on January 17, 2019. - Russian President Vladimir Putin on January 17, 2019 called for stability in the Balkans during a pageantry-filled visit to Serbia, a key Moscow ally in a tense region on Europe's edge. Although Serbia and all of its neighbours aspire to join the European Union, Belgrade has nurtured close ties with Russia, its historical "Orthodox big brother" whose people also share Slavic origins. (Photo by ANDREJ ISAKOVIC / AFP)