Mk Ultra is the name of one of the CIA Mind control programs. (The MK stands for Mind Kontrol).
It was started in April 1953, as a successor of the Projects Artichoke and Bluebird. Mk Ultra is some kind of an umbrella, a framework project for approx.
150 other projects (most of which started with the initials MK) that over the years studied all conceivable ways to control and influence people’s perceptions, convictions, and, therefore, behavior.
Some of the techniques researched were hypnosis, conditioning, sensory deprivation, drugs, religious cults, microwaves, psychosurgery, brain implants, and even ESP (See also the Stargate Project and SRV).
The program was officially ended in 1963 and succeeded by MK-Search, which -behind the scenes – continued a lot of the MK Ultra research.
Most of the MK-Ultra records were deliberately destroyed by the CIA in 1972 to avoid exposure by a congressional investigation.
Note that “Ultra” is the name of the dept. within the NSA that is in charge of the interaction with aliens, and that it’s also reportedly the name of the underground base under the Archuleta plateau and peak, northeast of Dulce, New Mexico.