Titanic's Final Mystery (8pm, Smithsonian) - A new documentary investigates a century of theories behind the sinking of the Titanic and uncovers new forensic evidence that proves the most likely theory for the disaster.

God is the Bigger Elvis (8pm, HBO) - A documentary about a famous movie star from the late 1950s and early 1960s who walks away from Hollywood at the height of her fame to become a cloistered Benedictine nun. Here's more on Dolores Hart's fascinating story.

Community (8pm, NBC) - The war between Abed and Troy intensifies, prompting Jeff to try to negotiate a truce between the former best friends while the rest of the group choose sides.

Person of Interest (9pm, CBS) - The Machine produces five numbers linked to New York's crime families, which prompts Reese and Finch to suspect that Elias has plans for his competition.

Scandal (10pm, ABC) - An entertaining new series in which a former White House communications director, played by Kerry Washington (right), runs a Washington, D.C., crisis-management firm. Here's my "Scandal" review.

Being Elmo (10pm, UNC-TV) - This Independent Lens documentary, narrated by Whoopi Goldberg, tells the life story of Kevin Clash, the puppeteer behind the popular Sesame Street character, Elmo. It's pretty enchanting. Adrienne has a full review.

Awake (10pm, NBC) - Michael tries to end a delicate hostage crisis and negotiates with a patient who is threatening to blow up a mental hospital. Meanwhile, his sleepless nights adversely affect his life and work.