There was life on Mars, and the pyramids were built by giants. This is stated in the conclusions of the CIA project "Stargate" and the report "Exploration of Mars on May 22, 1984." However, these sensational data were obtained in an extremely dubious way, writes the British Daily Mail.
The agency in those years recruited people who claimed to have psychic abilities. Then they included binaural rhythms (simultaneous listening to sounds at different frequencies) and semi-synchronized audio to induce altered states of consciousness, "separate the spirit from the body and send it traveling through the astral."
So one subject got to Mars about a million years before our era and found out that on Mars had pyramids similar to the Egyptian ones, but then the giants had to look for "a new place to live, because their environment was spoiled."
With the help of this project, the CIA "wanted to create spies capable of reading minds and penetrating the minds of enemies in order to fight The Soviet Union."
Note that a similar plot is implemented in the popular American TV series "Very Strange Things", which describes the CIA laboratory, where children were taught such abilities to fight the USSR.