Institute of Illegal Images

Housed in Mark McCloud's Victorian home in San Francisco's Mission District, the Institute of Illegal Images holds the world's largest collection of LSD blotter art — over 33,000 sheets and hundreds of framed pieces. Named for the era when merely possessing the perforated paper could be treated as evidence of a crime, it reframes a psychedelic-era ephemeral form as serious American folk art, and survived two federal prosecutions of its founder. It is open to the public free of charge.