CTU meaning in Governmental ?

24 is an American action drama television series created by Joel Surnow and Robert Cochran for Fox. The series stars Kiefer Sutherland as counter-terrorist agent Jack Bauer. Each season covers 24 consecutive hours in Bauer's life using the real time method of narration. Multiple interrelated plots are featured in each episode, which often include Bauer's contacts in perilous crisis. The show premiered on November 6, 2001 and spanned 204 episodes over nine seasons, with the season eight finale broadcast on May 24, 2010. In addition, the television film 24: Redemption aired between seasons six and seven, on November 23, 2008. The show returned with its ninth season titled 24: Live Another Day, which aired from May 5 to July 14, 2014. 24 is a joint production by Imagine Television and 20th Century Fox Television.

The series begins with Bauer working for the Los Angeles–based Counter Terrorist Unit, in which he is a highly proficient agent with an "ends justify the means" approach. This disregard for conventional morality puts him at odds with others until he is usually proven right. Throughout the series, most of the main plot elements unfold like a political thriller, as they lead to deaths, twists and cliffhanger endings. Bauer uses people on both sides of the law in his attempts to prevent terrorist attacks and bring down those responsible, sometimes at great personal expense. These attacks include presidential assassination attempts, bomb detonations, bioterrorism, cyberwarfare, as well as conspiracies that involve government and corporate corruption.

24 won numerous awards throughout its run, including Best Drama Series at the 2004 Golden Globe Awards and Outstanding Drama Series at the 2006 Primetime Emmy Awards. Its success spawned a spin-off series, 24: Legacy, that premiered on February 5, 2017. It used the same format but followed different characters and lasted one season. At the conclusion of its eighth season, 24 became the longest-running U.S. espionage or counterterrorism-themed television drama, surpassing both Mission: Impossible and the UK's The Avengers.