Nikita: Maggie Q returns for the last six episodes of the show’s fourth season. (SVEN FRENZEL/THE CW)

Television’s night of JFK-related programming begins with the History Channel’s “JFK Assassination: The Definitive Guide” (8 p.m.), a two-hour special that goes inside the facts and theories surrounding the most speculated-upon assassination in presidential history.

The special “Doctor Who: Explained” (BBC America at 8) explores the mysterious and two-hearted alien who is the Doctor with exclusive interviews with cast members from the show’s 50-year history.

Television journalist Tom Brokaw looks back at Nov. 22, 1963, in “Where Were You: The Day JFK Died” (NBC at 9). This in-depth documentary includes archival footage and in-person stories and explores the impact of JFK’s death on the country and the world.

RETURNING SHOW: Returning for its fourth season, “Nikita” (CW at 9) has Nikita on the run after being framed for assassinating the president. She tries to follow a lead that could clear her name and is unexpectedly reunited with her old team.

On Nov. 23, 1963, a television legend began, and the “Doctor Who” docu-drama “An Adventure in Space and Time” (BBC America at 9) aims to tell you its gen­esis story, from its struggles to its ultimate triumphs. Travel back in time like the Time Lord and witness First Doctor William Hartnell and the unlikely production team behind the series.

The part-documentary and part-concert special “Nashville 2.0” (WMPB at 9:30 and WETA at 10) looks at the current state of Americana music with a slew of performances from the likes of Alabama Shakes, the Avett Brothers, Rosanne Cash, Emmylou Harris and many, many more.

“Lee Harvey Oswald: 48 Hours to Live” (History at 10) chronicles the life of the enigmatic Oswald and his actions following the assassination of JFK. Using archival evidence and documents, the extensive special promises to tell a familiar story in an unfamiliar way.’s second attempt at original programming is “Betas” (Amazon), a Silicon Valley-set comedy in which a group of friends have an app and a plan but run into problems when they try to find an investor. You can watch the first three episodes for free online.

Television personality Howard Stern and comedian Adrienne Iapalucci come to the “Late Show With David Letterman” (CBS at 11:35).

Actor Jim Parsons and filmmaker John Downer join “The Tonight Show With Jay Leno” (NBC at 11:35), along with a musical performance from Cassadee Pope.

Comedian Sarah Silverman and magician David Blaine are on “Jimmy Kimmel Live” (ABC at 11:35), with music from Charlie Wilson.

— Rachel Lubitz