Trivia: The child-actor playing young Selene is actually the daughter of adult Selene's actress Kate Beckinsale.
Trivia: As a bit of an easter-egg, Mel Gibson included a single-frame of an actor dressed as Wally/Waldo from the "Where's Wally/Waldo?" book series in the theatrical version of the film. It was reportedly seen as being in poor taste, so it was removed from the initial DVD release. However, he was allegedly added back into the film for the Blu-Ray release.
Trivia: This movie was filmed back-to-back with Letters from Iwo Jima, a fictional account of the battle of Iwo Jima that looks at it from the Japanese soldier's perspective.
Trivia: At the time of the filming, the St. Charles Streetcars were not running 100%. When they show the Canal St Car, one sense that shows the car running on the right side tracks toward the camera, it's actually on the wrong side. Later when he's going to her apartment, one shot shows the streetcar running on the right side tracks (as the norm), and the trolley poles are up. Later when he gets off the car, it's on the opposite side, wrong direction, rear pole is down, and he gets out through the rear door as if it was main door.
Trivia: The plot of the movie is based on a 1934 play Thunderstorm by Yu Cao, a Chinese playwright, set in the 10th-century imperial China court. The Mandarin Chinese movie title is taken from the last line of a poem by a 9th-century rebel leader who was at war against the Tang Dynasty.
Trivia: The movie is based on a true story. Dieter Dengler was born in Germany just before WWII, and eventually left for the US. He told this story in the book "Little Dieter Needs to Fly" and a 1997 film (Werner Herzog) with the same same.
Trivia: A total of 500 boys auditioned for the lead role of Alex Rider.
Trivia: Jane Lynch plays Lucy Bobby, the mother of Ricky Bobby (Will Ferrell). In real life, Lynch is only seven years older than Ferrell.
Trivia: Anytime one of the characters click on "Do you want to meet a ghost?", they all click the "to".
Trivia: The Chitauri spiders attacking London resemble the alien machines from War of the Worlds.