Comment by Projectiboga

It was done at Harvard Divinity School in 1962

https://en.m.wikipedia.org/wiki/Marsh_Chapel_Experiment

The Marsh Chapel Experiment, also called the "Good Friday Experiment", was an experiment conducted on Good Friday, April 20, 1962 at Boston University's Marsh Chapel. Walter N. Pahnke, a graduate student in theology at Harvard Divinity School, designed the experiment under the supervision of Timothy Leary, Richard Alpert, and the Harvard Psilocybin Project.[1] Pahnke's experiment investigated whether psilocybin would act as a reliable entheogen in religiously predisposed subjects.[2]