The largest Turkish opposition party, the Republican People’s Party (CHP), holds its last rally in Ankara in the final countdown to the toughest election challenge of President Recep Tayyip Erdogan's two-decade rule. Kemal Kilicdaroglu, the CHP's leader and the six-party opposition's chosen candidate to challenge Erdogan, is currently leading in the polls with a slight advantage and within a whisker of breaking the 50-percent threshold needed to avoid a runoff on May 28. IMAGES