We were quite impressed with this series which deals primarily with the destructive rivalry between the CIA and the FBI in the years leading up to the 9/11 attacks. It is well written, well paced and extremely gripping. It is based on a book by Lawrence Wright that has a broader canvas--the origins and development of the Islamist movement in the late 20th century and how that was influential in the genesis of the various terrorist groups leading up with Al Qaeda.
https://www.hulu.com/press/show/the-looming-tower/
https://www.hulu.com/press/show/the-looming-tower/