Memorabilia from the long fight to legalize marijuana hang in Castro District home where Dennis Peron once lived. Peron was an advocate for the medical use of cannabis during the AIDS crisis, and ultimately authored Proposition 215, which voters approved in 1996, legalizing the sale and use of cannabis with a doctor's recommendation.

Stuart Watts is the founder of Green Guide Tours -- a company offering bus tours of San Francisco that explore the city's rich and contentious history with the prohibition and legalization of cannabis.