TV HIGHLIGHTS

Christmas in Rockefeller Center, 8 PM on Ch. 2 and

Ch. 5: The annual lighting of the holiday tree — this time, a Norway spruce from State College, Pa. — in the heart of New York is celebrated again in this special. Before that moment happens, those providing musical performances include Gwen Stefani, Pentatonix, Jennifer Nettles, Brett Eldredge, “Hamilton” Tony Award winner Leslie Odom Jr. and the Tenors. “Today’s” Matt Lauer, Savannah Guthrie, Al Roker and Hoda Kotb are the hosts.

Vikings, 9 PM on HIST;

1:03 AM on HIST: As the action-packed historical drama opens its fifth season with the two-hour episode “The Departed,” the death of Ragnar Lothbrok is still being felt as his ruthless son Ivar the Boneless (Alex Hogh Andersen) asserts his authority over the Great Heathen Army that threatens the very heart of England. As the troops of Ivar and his brothers prepare to take York, it falls to Heahmund (new cast member Jonathan Rhys Meyers), the so-called warrior bishop, to rally the Saxon defense.

Bruno Mars: 24K Magic Live at the Apollo, 10 PM

on Ch. 7 and Ch. 12: The Grammy-winning music superstar has been no stranger to television, but even after such occasions as well-received Super Bowl halftime appearances, he’s never had a broadcast-network special to call his own ... until now. Recorded at the iconic New York showplace, the hour features Mars in typically energetic performances of his biggest tunes to date. He’s not limited to that stage, though, since he and the members of his Hooligans band also hit the streets of thecity.