BOGOTA, COLOMBIA - OCTOBER 02:  Colombia's President Juan Manuel Santos (C) casts his ballot in the referendum on a peace accord to end the 52-year-old guerrilla war between the FARC and the state on October 2, 2016 in Bogota, Colombia. The guerrilla war is the longest-running armed conflict in the Americas and has left 220,000 dead. The plan calls for a disarmament and re-integration of most of the estimated 7,000 FARC fighters.  (Photo by Mario Tama/Getty Images)