On April 20, the legendary annual 420 gathering "Hippie Hill" will take place at Robin Williams Meadow in San Francisco's Golden Gate Park. Since the Summer of Love in 1967, Hippie Hill near Haight Street has been a counterculture gathering spot and the free event brings thousands of people together to celebrate the right to use cannabis. Live music and event programming will run from 10 am to 5 pm. There is no ticketing or registration required, so all you have to do is grab a blanket, pack a lunch, and come with an open mind as you’ll see all kinds of things throughout the open-air venue.