When Trevor lights up the flare and the wall sets on fire because of the magnesium, he's supposed to burn himself. The scene in the movie was the second take of the day and in that take Brendan Fraser did burn himself for real. He was holding the road flare too perpendicular and too close in relation of the wall, so the flames bounced on the wall and blew back to his bare hand. The screams he makes were a mix of real pain and acting. The production was shut down for a few days.
When Trevor opens the box of stuff belonging to his lost brother, he pulls out an odd wooden item, declares that he doesn't know what it is, and sets it aside. The item is a Holmes Stereoscope, a device designed in 1861 by the American physician and writer, Oliver Wendell Holmes for the viewing of so-called "stereocards". A stereocard is like a postcard which has a left-view and right-view photograph mounted alongside one another. When viewed through this stereoscope, the photographs are merged into one 3-D image (a process later adopted for the ViewMaster viewers and cards). The Holmes Stereoscope was a great source of entertainment in the Victorian era. It was, in a sense, the home entertainment center of its day, as it transported its users to exotic places all over the world. Thus, a character in a 3-D movie having no idea what a stereoscope is makes for a cute little 3-D in-joke.
When Trevor cleans his house to prepare for the arrival of his nephew, he places some plates on top of a book titled, "Exploring the Deep Frontier: The Adventure of Man in the Sea" written by Dr. Sylvia Earle. Dr. Earle holds the record for the deepest untethered ocean dive (1250 feet) to the bottom of the ocean.
Hannah tells Trevor that she will charge him 5,000 krona (ISK) an hour to guide him. At the time of the film's release, that was roughly $65.00 USD. If he was to pay in rolls of quarters, as his nephew suggested, that would be approximately 6.5 rolls of quarters per hour.
Independent film maker Paul Chart (American Perfekt (1997)) was originally signed to write and direct the picture and penned the original script. Chart left the project, however, after a decision was made to shoot the film in 3-D, uncomfortable with the possibility it would become more 'theme park ride' than the epic action-adventure film he envisioned. The Jules Verne novel was apparently one of his favorite pieces of literature. Chart was ultimately replaced with effects specialist Eric Brevig and the script was heavily retooled to emphasize the new 3-D format.
Physics error: when calculating the distance of the depth, Brendan Fraiser makes the mistake of multiplying 32*t^2, when it should be 16*t^2. It comes from the physics equation for distance x1=x0+v0*t+(1/2)*a*t^2, where a in this case is gravity, at 9.8 m/s^2, or 32ft/s^2.