This show kind of has it all. It is full of suspense, full of surprises and has high stakes. One season takes place in one day and has 24 one hour episodes meaning that it is presented in real time.
It is kind of topical today, on the 17th anniversary of the September 11 attacks that i'm posting a show that covers terrorism. The intelligence services don't get enough credit for what they do in keeping us safe.
24 (2001-2010, revived 2014 for one season)