1.It might be difficult to see from this angle, but the fourth smoke stack doesn't emit as much smoke as the other three. This is a true-to-life detail as only three of the four stacks were connected to the ship's furnaces.
2.At the end of the movie when Jack and Rose meet by the clock, the clock reads 2:20. In real life, the Titanic sank at 2:20 a.m.
3.At the very beginning of the movie, one of the items Jack and Fabrizio win in the card game is a pocket knife. When the ship is sinking, Fabrizio uses that same knife to cut down a lifeboat.
4.Speaking of the poker game, Jack shows a mean poker face when drawing his winning card — it was a tense moment. In reality, he already had three of a kind and would've won the game regardless.
5.In one of the earlier scenes, James Cameron recreated this actual photo (left) of a boy spinning a top on the deck of the Titanic.
6.During this heart-wrenching scene where a mother is trying to soothe her children as the ship sinks, she tells them of Tír na nÓg, which is paradise in Celtic mythology. Another name for it is "Tír fo Thuinn," which translates to "Land Under The Wave," as one of the methods for getting there is by going under water.
7.An inquiry made in 1912, shortly after the tragedy, found that there were 37 seconds between when the iceberg was spotted and when it made contact with the ship. In the film, Cameron made sure the scene between the spotting and the impact lasted precisely 37 seconds.
8.Remember this guy? Jack and Rose encounter him on the deck as the ship is going down. Did you know he's based on an actual Titanic survivor by the name of Charles Joughin, who was the chief baker and one of the best paid crewman on the ship?
9.The man and woman that lie in bed together as their room floods are also based on real people: Isidor and Ida Straus, co-owners of Macy's Department Store.
10.Also, this actual artifact recovered from the wreckage (left) looks suspiciously similar to that infamous "door" that's been so hotly debated since the movie's release over 20 years ago.
11.Despite Cameron's apparent obsession with true-to-life details, he still got the sky wrong in the original theatrical release. Instead of an actual night sky, it was just a random assortment of barely visible white dots — he corrected this in the 2012 rerelease after being called out by Neil DeGrasse Tyson.
12.The 1912 Renault Type CB Coupe de Ville being hoisted onto the ship at the beginning is the same one in which Jack and Rose have sex later on. And guess what? There actually was one of these aboard the Titanic, and there were even several failed expeditions trying to locate it at the bottom of the Atlantic Ocean.
13.The scene in which Thomas Andrews, upon realizing that the ship he designed is sinking, rests both hands on the mantle and stares into the clock is a nod to an almost identical moment in A Night to Remember (1958), which is also about the Titanic tragedy.
14.At one point Jack tells Rose he'll take her to the Santa Monica Pier where they'll "ride on the rollercoaster til [they] throw up, then [...] ride horses on the beach, right in the surf." At the end, when it's panning through Rose's old photos, there's one of her on horseback with the Santa Monica Pier in the background.
15.And at the very beginning of the movie when we first meet Rose, she's wearing this box-y, heart-shaped necklace. We know she had the Heart of the Ocean all along, but had she been wearing it too?