Factual error: In the episode where Sydney is supposed to be in Helsinki, there are visible skyscrapers in the background. There are no skyscrapers in Helsinki.
Factual error: In this episode we see Blithe get shot in the neck and are told that he died in 1948. In reality he was shot in the shoulder and survived. He later served in Korea and was promoted to master sergeant as well as receiving the paratrooper of the year award. Blithe died in 1967 while on active duty in Germany.
Day 4: 2:00 P.M.-3:00 P.M. - S4-E8
Factual error: When Edgar proves that Mary-Ann Taylor framed Sarah to be the rat in CTU, he claims that she remotely took control of her computer by sending the signal over "a plain old AC power line." This is not possible, unless the computers were equipped with special hardware to separate the AC from the signal. If they were, this traffic would have been observed by James Heller's assistant.
Factual error: Lex crashes and his car lands on its roof, but in the span of a few seconds it has sunk straight to the bottom, and turned the right way up. Cars don't sink that quickly. (00:17:25)
Factual error: Aetius' troops don't look anything like 5th century Roman soldiers. They are carrying a large rectangular shield, a pilum (a spear which was used for throwing) and a sword (gladius) on their right. This was typical for the Roman army until about the 3rd century A.D. In Aetius' time, the soldiers would have had smaller oval shields, a hasta (a lance used for stabbing and for fending off cavalry attacks) and a sword (spatha) on their left. Also, there would be an enormous amount of "barbarian" mercenaries in the Roman army (Goths, Vandals, even Huns.), so it was hardly a Roman army anymore. And where's Aetius' cavalry?
Factual error: Each time Adam Kane appears as a hologram, you can hear the sounds of his footsteps. A hologram would not make a sound other than the projected voice.
Factual error: In the beginning, when the stranger kills the brumby with his rifle, you can see that the horse is still breathing when he is driving off. Also later, when the girls find the horse, you see it breathing. (Check the stomach near the legs.)
Factual error: In the scene where J.D goes to Elliot's apartment and finds Dan there he sings along to "Thank you" by Dido. However that song is from the album "No Angel". The album cover shown in the episode is "Life for rent" which doesn't feature the song.
Factual error: When the cops need to arrest a medical professional, they are frequently shown barging into his/her office, exam room, or even operating room. This would never happen in real life and is strictly forbidden, as it is a gross violation of the patient's privacy, and in the case of the OR, could contaminate the sterile environment, thereby jeopardizing patient safety as well.
There's No Place Like Home - S2-E1
Factual error: This is at the end of the episode, when Jordan takes the key that she found for the 66 Ford and tries it in the ignition it should have been a square key. Round keys were for the doors and trunk. Back then they made two keys - one that opened the car doors and trunk and one that started the ignition. She never even tried the key in the trunk.