Factual error: As Ben is clinging to the staircase while it is falling apart, there is a close-up of a nail being pulled out of the wood. This nail is round-headed, rather than square as it would have been over 200 years ago. It's also shiny instead of rusty, which indicates that it's galvanized. Galvanization as an industrial, metal-preservation process was not patented until 1837, and was not used in building materials until well into the late-1800s. Since the film states the staircase was made by "the Founding Fathers, " and there was no galvanization of iron nails in any industrialized nation in 1780s-1830's, this is a huge anachronism.
Factual error: When Ben, Abigail, and Riley are discussing the correct time to be at Independence Hall, they would need to know the exact date, not only the time, of the painting to be sure to see the correct shadow.
Factual error: When Ben and the rest of the group start to climb under the church, Ben moves some spider webs out of the way with his torch. The dust on the spider webs would have burst into flames when he did this, but instead they just fall to the side.
Factual error: The sun's location horizontally changes throughout the year. Because of this, Ben, Abigail, and Riley shouldn't know where the shadow is falling, horizontally.
Factual error: When Dr. Chase receives the Washington campaign button from Ben Gates, she immediately picks it up with her bare fingers and rubs it with her thumb. An expert collector would *never* handle metal objects with their bare hands like this, as the acid on the fingers will corrode the metal. Cleaning the coin afterwards is also not an option, as this presents an even higher damage risk to the coin. See http://www.stujoe.com/content/view/30/34/ for more details on this subject.
Factual error: During the heist preparation scene, Riley enters the National Archives Metro station to record surveillance camera footage. Surveillance camera feeds for the National Archives would never be accessible within a Metro station due to both security concerns and the fact that the feeds are not needed outside of the National Archives building. (00:32:00)
Factual error: When Ben finds Charlotte buried in the ice, he would have encountered solid, thick ice. The small pick-ax he uses seems to easily break through the ice. Also, he seems to be digging through packed snow, rather than thick ice, which is indicative to the Arctic ice shelves.
Factual error: In the scene under the Trinity Church in New York, on the wall are two metal support beams in the shape of an X. There are bolts and washers securing the beams. Judging by the elevators that are operated by pulleys, there should be wood with square nails in the time period which the underground passage was built. Seeing the total state of disrepair in the underground elevator shaft, it is extremely unlikely that any updates/repairs were made significantly later than the time it was originally built.
Factual error: The security to get into Independence Hall is very strict, since the terrorist attacks on September 11, 2001. Security would not have allowed Ben to keep his pocket knife when he entered it. This should not be confused with his disguising as a janitor, as this happened at a different location (National Archives) earlier in the film.
Factual error: The National Archives room with the Declaration of Independence is actually darker than portrayed in the movie. The lack of light is for the protection of the documents, so that the writing doesn't fade away.
Factual error: In the scene when Ben, Abigail and Riley are on the tower of Independence Hall, they look at the shadow marking the secret place where the glasses are hidden. It is 3:20. The shadow of the cross is in the second third of the pillar. When Ian is on the tower the shadow has already moved to the top of the wall. As the others have left Independence Hall at 3:28 the shadow must have traveled the distance in about 4 minutes. This is far too quickly. (01:12:20)
Factual error: When Ben and Abigail and Riley separate at Independence park Abigail and Riley could not possibly have exited the park and run right into the Reading Terminal Market. Independence park (where the liberty bell is housed) is between 5th and 7th and Walnut Streets, and Reading Terminal Market (where Abigail hides from the bald man) is at 12th and Arch street. At least 15 blocks apart.
Factual error: To reveal the invisible ink on the back of the Declaration, Ben and Dr. Chase use pure lemon juice before warming the surface. This is best seen when Chase first test it out on the corner, where the Mason symbol is placed. Lemon juice is in fact also used as invisible ink (that you have to heat to make visible), and this procedure would have ruined anything written on the back of the document.
Factual error: In the scene in the Charlotte, the black powder would not burn without creating enormous amounts of thick grey smoke. And the barrels would never have exploded like that. Maybe one or two but never to that degree. More like a succession of explosions.
Factual error: Ben, Riley, and Abigail are driving into Philadelphia at sunrise to go to the Franklin Institute. They are shown driving west on the Ben Franklin Bridge. The sun is actually setting in the west behind Philadelphia, not rising. (01:07:00)
Factual error: On the back of the Declaration of Independence when the Masonic square and compass are revealed, there is a "G" in the center. This "G" was not used until the period of the Civil War. Confederate Masons refused to use the "G" as they considered it a Yankee trick. Even today the Grand Lodge of England does not use the "G." For these reasons it would be unlikely that the Masonic symbol displayed on the Declaration would have included a "G."
Factual error: The ropes under Trinity Church are all shiny and new looking. These ropes would most likely be rotten and not able to hold up the massive chandelier or be supportive for the dumbwaiter system.