Project MKUltra:  The CIA’s Mind Control Prgramme
Although initially seen as another fanciful conspiracy theory, this one turned out to be true. The CIA really did run secret mind-control experiments on American citizens from  1950s until 1973, using “electronics, hypnosis, sensory deprivation and verbal and sexual abuse”. In 1995, President Bill Clinton issued a formal apology for Project MKUltra, as it was known. It is believed that ‘Unabomber’ Theodore Kaczynski was part of these experiments, although that detail has yet to be confirmed.

Reptilian Elite
The ‘reptoid hypothesis’ is a conspiracy theory which advances the argument that reptilian humanoids live among us with the intention of enslaving the human race. It has been championed by former BBC sports presenter David Icke who believes that deceased American comedian Bob Hope, members of the Royal Family and former US Presidents George W Bush and Bill Clinton are part of the “Anunnaki” race who came to earth for ‘monatomic gold’. Some critics accused Icke of anti-Semitism, alleging that his talk of reptiles was code for Jews – but he clarified that the lizards to which he referred were literal, not metaphorical.

CIA created AIDS
Since the Centres for Disease Control and Prevention first reported the HIV/AIDS epidemic in 1981, rumours have persisted that the deadly virus was created by the CIA to wipe out homosexuals and African Americans. Even today, the conspiracy theory has a number of high-profile believers. South African President Thabo Mbeki once touted the theory, disputing scientific claims that the virus originated in Africa and accusing the US government of manufacturing the disease in military labs. When she won the Nobel Peace Prize, Kenyan ecologist Wangari Maathai used the international spotlight to support that theory as well. Others insist that the government deliberately injected gay men with the virus during 1978 hepatitis-B experiments in New York, San Francisco and Los Angeles. Still others point to Richard Nixon, who combined the US Army’s biowarfare department with the National Cancer Institute in 1971. Though the co-discoverers of HIV — Dr. Robert Gallo of the National Cancer Institute and Dr. Luc Montagnier of the Pasteur Institute in Paris — don’t agree on its origins, most members of the scientific community believe the virus jumped from monkeys to humans some time during
the 1930s.
Source: The Week and Time