Factual error: Trevor - a Professor of Geology - boasts about having an article published in Scientific American, and that is not something any scientist would do. Scientific American is looked upon with slight disdain by the scientific community, considered to be a populist crowd pleaser. It is not even peer reviewed. Considering that he has just turned the geological and archaeological worlds on their heads he would have been better off publishing in Journal of Geological Research or Geology, both prestigious professional journals.
Factual error: Basic physics - Hancock throws Michel from a dead stop to above cloud level in about eleven seconds. The clouds are bog standard cumulus which form at around 7,000 metres in temperate zones. This means that Michel accelerates to about 700 metres per second instantly, from a dead stop. Obviously he cannot accelerate during his ascent, so his starting speed has to be at least that. (In fact he would have to start his ascent much, much faster than 700 metres per second as he would be constantly decelerating due to gravity and air resistance, but it will do as a start point.) Michel accelerates from 0 to 2,520 kilometres per hour - twice the speed of sound - in zero seconds. He would be accelerating at around 5000 Gs, turning him into a very long streak of fine, pink mist.
Factual error: After escaping the hospital, Harvey Dent wears the same charred suit he was wearing when he was brought to the hospital. That suit would not have been neatly taken off and left intact. It would have been cut off with shears so as not to accidentally remove any damaged skin and flesh when pulling the pants and shirt off. The blazer might still be intact but certainly not the pants and shirt.
Factual error: In the very first scene a giant squid swims past Fujimoto. It swims in the wrong direction however, with its tentacles in front. In reality squid swim backwards.
Factual error: Near the beginning of the film, Calico is sitting with a cat on his right shoulder. Their reflection is shown in the glasses of a man directly opposite. The reflection shows Calico and the cat in the same position instead of being reversed, as a reflection would be. (00:04:30)
Factual error: Benjamin leaves his family at some point after his daughter's first birthday (1970), and definitely before her second birthday. But a 1973-1977 El Camino is parked in front of their house as he rides away on his motorcycle. (02:24:15)
Factual error: The Moon is pushed into a "more elliptical" orbit. When the orbit it shown, it is more eccentric than the Moon's real orbit. However, it is centered directly on the Earth. This violates Kepler's first law of motion, which states that a natural satellite has the primary body at one focus of an elliptical orbit. In other words, the Moon should come much closer to the Earth at one end of the ellipse, and recede very far from it at the other end, rather than receding to the same distance in both directions.
Factual error: When it says that in 2 nights the moon will hide (New Moon) but the image that shows the moon is in waxing crescent phase, when it must be in waning crescent. (01:09:30)
Factual error: In the beginning dialogue when the narrator is talking about the locked box being passed down from mayor to mayor, when it reaches the 7th mayor, the counter is at 47. Later, when Lina is delivering a message to the current mayor, she stops at the portrait of the 7th mayor and says it is her ancestor. In that portrait, the box is visible under his arm with the counter showing 120.
Factual error: When Kendall is about to implode the school, the demolition practices are completely unfeasible. The school would be completely gutted, with all glass, copper, and plumbing removed (the building simply looks cleaned out a bit); additionally, significant structural damage would be intentionally introduced to weaken the internal support (every wall is largely cored); further, the school building and/or surrounding buildings would be sealed in tarps to minimize damage spread; finally, the crowd of protesters and onlookers would be at least a quarter-mile away. Even given this is a bit of a fairy-tale story, the demolition techniques are completely incorrect on several levels.
Factual error: When Cam ambushes Ba'al in 1939, he has two Thompson M1 submachine guns. The M1 version of the Thompson wasn't developed until 1942.
Factual error: The Volkswagen Campervan that is used at the beginning of the film has a Zürich number plate, yet the cantonal coat of arms to the right of the number plate is that of the canton of Ticino (red and blue stripe). This is incorrect: The coat of arms should have been a white-blue stripe, which is the coat of arms of Zürich Canton and would correspond correctly to the number plate.