Two retired men fish off a bridge in Mariupol, Ukraine.
MARIUPOL, Ukraine — This is Ukraine’s Russian-speaking industrial heartland, and if Vladimir Putin decides to invade more than just Crimea, this region is probably where he'll start.
But even if his troops hold back, an escalating rift between east and west Ukraine means this region will remain a political tinderbox, especially if life for ordinary people gets tougher.