Short answers, pulled from the story.
The tragedy involving James Barnes began on the 2nd of May 1991 when a brainwashed super-soldier intercepted a car carrying super-soldier serum in Siberia. This event set the stage for the conflict that would tear the Avengers apart in 2016.
The terrorist attack that catalyzed the Sokovia Accords took place in Lagos, Nigeria. Brock Rumlow carried out the attack which resulted in the accidental death of several Wakandan humanitarian workers.
The 2016 film Captain America: Civil War was directed by Anthony and Joe Russo. The directors previously worked on the psychological thriller Seven and the crime drama Fargo.
Captain America: Civil War grossed over $1.1 billion worldwide. This financial success was a testament to the film's ability to resonate with audiences on a deeper level.
Tony Stark felt a moral obligation to submit to authority after the destruction of Sokovia and the creation of Ultron. He carried a deep sense of guilt for the destruction that followed his creation of the sentient AI.