One of the most indelible images of Steven Spielberg’s 1998 film Saving Private Ryan, which kicks off with an unforgettable recreation of the famous D-Day invasion, is the troops in the landing craft right before they hit the beaches, vomiting on one another. Knowing the sheer horror they were about to face on the sandy battlefield in France, the safe assumption for their throwing up would be from anxiety — a nervous reaction.

But, that guess wouldn’t be accurate. Entirely, that is.

According to the creators of the following video, “History Buffs” (host Nick Hodges), the vomiting was due to two things: being fed a overly enormous meal prior to shipping out on the tiny boats, and sea sickness. Which is felt much more, and has a greater effect on smaller vessels.

Crazy, huh? Well, there’s that and so much more in the following breakdown, which examines the historical accuracy within arguably the greatest World War II film ever made.

The overall/headline finding? The movie is precise, although there are falsehoods and stretches in between. But many of the minor details are true, which is a bellwether for the authenticity of a truth-based work, and the care  and time invested.

The squad also looks at other big ticket films, like Amadeus, Lawrence of Arabia, Waterloo, Braveheart and even Goodfellas.