Bicyclists hit San Francisco to celebrate the 20th anniversary of Critical Mass

This week marks the 20th anniversary of Critical Mass, the monthly bicycling event which brings riders together to explore their city on two wheels. Critical Mass began in San Francisco in 1992, and now takes place in more than 300 cities around the world. All week long in San Francisco there will be celebratory events, including the screening of a short documentary about Critical Mass, a Critical Mass book release party, games, live music, and more.