Mix Up (1986)

One of the most remarkable and innovative documentaries ever made, this film follows the famous true story of two English women who as babies got switched in the hospital and 20 years later discovered that they'd been raised by the wrong sets of parents. Romand enlists all the surviving family members in her haunting and bizarre investigation, which involves not only a recounting but a reenactment of all the significant events in the two daughters' emotional histories.