2015’s defining moments on CNN

ANOTHER year of terror, as IS (or Islamic State) expands its reach beyond Iraq and Syria, staging attacks in Lebanon, Egypt and France; the Syrian refugee crisis intensifies across Europe; in the United States, victory for marriage equality; and one man dominates the presidential campaign. These are among the stories that defined 2015.

CNN’s Michael Holmes, Isha Sesay, Robyn Curnow, Paula Newton and Samuel Burke discuss the most riveting stories of the year in an hour-long special. The network was there on the front lines in Paris, Athens, Havana and across the globe, as major events unfolded. Tune in on Dec. 25 at 9 a.m. or 4 p.m., with replays on Jan. 1, 2016.