Lysergic acid diethylamide, commonly known as LSD, is a potent psychedelic that can cause hallucinations, sensory enhancement and an altered state of consciousness. As humans have a habit of mixing drugs with sex, it comes as no surprise we've been experimenting with LSD for decades.

The summer of love

On the brisk morning of January 14, 1967, hundreds of long-haired, open-minded "hippies" gathered for the Human Be-In music festival. LSD was distributed among the crowd as speakers such as Timothy Leary encouraged festival-goers to "Turn on, tune in, [and] drop out." The festival spearheaded the so-called Summer of Love, a movement that included about 100,000 people gathered in the Haight-Ashbury district of San Francisco to experiment with psychedelics and protest the Vietnam War, among other things.

Leary, who seven years earlier had founded the Harvard Psilocybin Project with Richard