Factual error: The 'Mayor' says he's a Turtle, but he's actually a Tortoise. Turtles have paddle type limbs for swimming, not reptile like paws as depicted in the movie.
Factual error: When Jason Bateman first meets the rookies at the roadblock, some Saguaro cacti can be seen in the background. Saguaro are not indigenous to Nevada.
Factual error: When they are in paradise the law enforcement is all wrong from the uniforms to the cars. In the State of Ohio, every county Sheriff Department looks the same (black and gold cars, black uniform shirt, grey pants, stetson style hat), they are all regulated by the Buckeye State Sheriff's Association. In the movie the "local sheriff" wears a brown uniform and drives a car with white doors. This is not accurate. The front and back of the car is accurate with the gold stripes, and the license plates on the cars are also accurate, but those are the only parts of the cars/uniforms true to the state of Ohio.
Factual error: Julia Roberts character orders Pizza and Wings, gives the driver one bill (guessing it's a $20). Says she's giving a $12 tip. No way Pizza and Wings costs $8, certainly not in California.
Factual error: While Hadrian's Wall itself is accurately depicted, its use and meaning to the Romans is not. The Wall did not demarcate a line north of which no Romans soldier would venture out of fear of the locals. The area north of the wall was too sparsely populated to produce a serious threat to a sizable Roman force and the Romans would have regularly patrolled there. In fact just two years after the events in the movie are set, the Romans constructed the Antonine Wall 60 miles north of Hadrian's Wall, running approximately between today's Glasgow and Edinburgh. The plot more closely matches the experience of the Romans in Germania in AD9 when three Roman legions were wiped out in the Teutoburg Forest. The Romans went to great lengths to recover the Eagles lost in this defeat and did so through a combination of diplomacy and military successes.
Factual error: In the helicopter scene, the assassin is using a Gatling-type weapon with a set of rotating barrels. However, the fire is coming out of the central spot where the axis should be. That's not how Gatling guns work. (00:42:25)
Factual error: The security guard in the bank is carrying a revolver as a sidearm but has semi-automatic magazine pouches on his duty belt.
Factual error: The scene showing Paris at night displays heavy traffic and bright car headlights over the distance. Both were not possible to be seen at time the story occurs, circa 1920's.
Factual error: When Benjamin's brother arrives in his car with the bear's fish, he opens the trunk with a remote key. The car is a Mercedes 240 Diesel (to be more precise, a W123 series), built from 1975 to 1986. Mercedes first introduced a remote key system to the W140 series at the beginning of the nineties. (01:35:45)
Factual error: The young priest sees images of a red-eyed horse, but later, it is referred to as a mule, which looks much more like a donkey.
Factual error: The airplane that is used in the film they are watching at the start is a Ryan ST. The Ryan ST had it's first flight in 1935.
Factual error: Spoiler alert - When Henry's body is recovered under the 4th Street Bridge in Los Angeles, the 6th street bridge and the 7th street bridge (the one that he fell off) are each visible in the background. Meanwhile the water is visible moving towards the 7th street bridge which indicates that his corpse floated against the current. (00:22:20)
Factual error: Josh abseils forwards into the cave and in the next shot is seen coming alongside Victoria, in the standard seated abseil position. This would not have been possible, due to the design of his harness, without moving his abseil device from his back to his front. This would have involved him removing the device completely and then re-attaching it to the front of his harness which would be impossible during descent. (00:15:20)
Factual error: When Jamie answers Dylan's phone and his ex-girlfriend shouts and then hangs up, you can hear a hang up tone. This isn't possible on a cell phone.
Factual error: On the plane, Emma shows an issue of Hello! magazine featuring the heiress Grace is passing as. It's labeled as "number 1100, May 31 2010", but the May 31 2010 issue was actually number 1125. (00:30:30)
Factual error: When Andy is headed to Mr. Simon's house, a white 90s Lincoln Town Car can been seen in the background, out of place for the 1965 setting. (01:31:45)
Factual error: The car doors wouldn't protect Adam and the other police officers from being shot - they offer no protection against bullets.
Factual error: Danny Greene has a bomb placed in Shondor Birns' car. As Birns is waiting to cross the sidewalk, the pedestrian walk-don't walk sign is a modern digital sign, that was not around in 1975.
Factual error: Mallory tells Florence that the school is in Cumbria. Cumbria didn't exist in 1921. It was created in 1974 from Cumberland, Westmorland and part of Lancashire.
Factual error: Jerry digs up a natural gas pipeline in the backyard and jerks it so hard that a pipe coupling in Charlie's house breaks, venting natural gas into the house for about 4 seconds. Then Jerry uses a cigarette lighter to send a flame through the pipeline, exploding Charlie's house like a fire bomb, catching virtually every room in the house on fire. In reality, it would take an hour or more for vented natural gas to accumulate sufficiently to blow up a house, for one thing. For another thing, Jerry broke the gas pipeline in the backyard in order to ignite it; so, while the broken pipeline leading to Charlie's house had no gas pressure, the pressurized side of the pipeline was still in the backyard with Jerry. Meaning, Jerry himself should have been engulfed in fire as soon as he sparked a flame.