Welcome to the Central Intelligence Agency’s Freedom of Information Act Electronic Reading Room. Do UFOs fascinate you? Are you a history buff who wants to learn more about the Bay of Pigs, Vietnam or the A-12 Oxcart? Have stories about spies always fascinated you? You can find information about all of these topics and more in the Central Intelligence Agency (CIA) Freedom of Information Act (FOIA) Electronic Reading Room.

Source: Freedom of Information Act Electronic Reading Room | CIA FOIA (foia.cia.gov)

Apparently the CIA has just released 12m documents into this

The CIA Just Dumped 12 Million Declassified Documents Online