Special counsel Robert Mueller's team has reportedly begun writing its formal report on the investigation into ties between the Trump presidential campaign and Russia, according to CNN.

The big picture: What a wild ride it's been. Since day one, President Trump has criticized the investigation, calling it a witch hunt and rejecting the idea that there was ever any collusion or foul play in his campaign. But that hasn't slowed Mueller down.

We compiled the 10 most significant moments of Mueller's investigation: