Factual error: When Buddy and the musicians tour bus is towed to the Clear Lake Auditorium for the final concert before the fatal air crash, the canopy states that the concert is on the 3rd of February. The fatal accident that took Buddy, The Big Bopper and Ritchie Valens occurred at 1am on 3rd February 1959 so the canopy should have read 2nd February.
Factual error: The film strongly implies that John Dudley, the Duke of Northumberland, keeps his head (literally) by converting to Catholicism. In fact, he was executed well before Lady Jane Grey was.
Factual error: Just after the start of the Korean War, McArthur places a map of Korea on the hood of a jeep to explain to a subordinate general his plans to invade Inchon. The map shows the boundary of North and South Korea not along the 38th parallel, which was the border at the time (1950), but along today's DMZ - not established until the Korean armistice was signed in 1953.
Factual error: At the end of the film, Mary Magdalene approaches Jesus just as he has arisen from his tomb, at first shocked that he has arisen. As Jesus is talking to her and motioning with his hands, it is plainly clear that he has no nail marks/stigmata, when he should have. (See John 20: 24-29, where-in the resurrected Jesus shows "Doubting Thomas" the nail prints in his hands.)
Factual error: When Richard asks Art his opinion of his book, a copy of "Haymarket Scrapbook" is on a shelf. This book was first published in 1986, yet Richard's book will be published in 1981. (01:03:00)
Factual error: The queen's maid tells Brown that the queen is currently reading 'Lord Tennyson.' That would be difficult in 1864, as Tennyson did not accept a peerage until the early 1880s.
Factual error: Towards the beginning of the film, the Cashes receive a notice about their rent. It's the 1950's and the address has a ZIP code. ZIP codes were not introduced until 1963.
Factual error: The song "I Won't Dance" was not written until the early-'30s, at least six years after the time it was shown being used in the film. However, it is still performed in the dining room scene.
Factual error: When Bonnie and Clyde are killed he is lying on the ground in front of the car, and she is in the driver seat. In real life they were both killed in the car. He was in the driver seat, and she was lying up against him. (01:44:20)
Factual error: A concrete barrier is shown around the White House in the 1960's. This was not put into place until the 1980's.
Factual error: When Mark Felt and the FBI Director are in a car on the way to the Watergate hearings in 1972 or 1973, from the car window, you see the WW2 memorial, which was built in 2004.
Factual error: In a picture from the UN headquarters in New York in the year 2003 you see two German flags. The German Democrativ Republic hasn't existed since 1990. (01:16:04)
Factual error: This film shows Sellers faking a broken leg in order to get out of playing the pilot in Dr. Strangelove. Sellers fell off a ladder on the set of the film, and director Stanley Kubrick was there to see it happen. He broke his leg and was replaced by Slim Pickens as a result.
Factual error: When Desmond's father is in his WW1 uniform, to the far right he is wearing a French Croix de Guerre (Cross of War) - the medals themselves are identical however, this decoration incorrectly hangs from a WW2 type ribbon.
Factual error: There are Velcro straps holding the pads on the blocking sled, and there is an end zone goal post with one base. Both of these items did not exist until the late 60s.
Factual error: Women's stockings had seams in 1944. When people are dancing at the party in Bayfield's apartment, the backs of women's legs appear in enough shots to show that their stockings, anachronistically, are seamless.
Factual error: During Howard's "Thank You" speech to New York he gives NYC the gift of a live performance by AC/DC. The year was 1985. As the band takes the stage and launches into "You Shook Me All Night" we see Phil Rudd on drums. Rudd had quit AC/DC two years earlier and was replaced by Simon Wright. (Rudd returned in 1994, hence being part of the band when the scene was filmed).
Factual error: Anne Frank received her diary on her birthday, and started writing on it 1 month before she went into hiding. In the movie however, she is presented with the diary on the first she arrives at the hiding place.
Suggested correction: Since this movie is based on actual events and not considered a documentary, then the film-makers are allowed to change things to their liking.
While I feel like this sort-of correction could apply to certain elements of movies based on true stories like dramatized scenes (since there has to be some condensation of time and some elements boosted for drama, which can be chalked up to filmmakers changing things), I think a film based on a true story contradicting a known hard fact like this should 100% count as a mistake. Otherwise, you could just as easily argue that any factual error in any film is invalid because the filmmakers are "allowed to change it."
Factual error: The view from the aircraft Jane is flown home from France in shows the modified double engine pod of the 747 famously at Dunsfold Airfield, Surrey. Also a late livery grey RAF VC-10 parked in the distance. Also the engines of the plane she is in are upgrades and not right for the year it is supposed to be happening. (01:23:20)
Factual error: The scene that takes place at the Ford release of their 1971 models has two Mustangs driving to the event. The one in front is obviously a 1973.