The CIA and the FBI share similar goals, but their missions and histories could not be further apart.
The FBI was founded more than 110 years ago, with Stanley Finch as its first director. At the time, terrorist attacks by Anarchists were on the rise, and the federal government needed a centralized agency to keep track of them and try to stop them. In time, the purpose of the FBI changed. The FBI took on the American mafia, and with the help of the Southern District of New York, helped prosecute the Five Families Case. It pursues cases of domestic terrorism, kidnapping, and even some cybercrime. Today, the FBI works to stop terrorism with the tools of domestic law enforcement, and it even stations a few officers overseas.
The CIA, on the other hand, came about after WW2 as a Cold War incarnation of the Office of Strategic Services, which was the American spy apparatus during WW2. The CIA isn't allowed to spy domestically, and thus most of the work they do in the USA is analysis. Their clandestine service agents travel the world in pursuit of intelligence which is sent back to Langley, Virginia, where the CIA makes sense of it and relays it to the White House, Department of Homeland Security, the military, and the FBI, as the case may be.
Do you think you're more of a G-man or more of a CIA spook? Now's the time to find out with this quiz!