A naked man pauses before heading into Mack Folsom Prison Sex Club in San Francisco after the Folsom Street Fair. The Folsom Street Fair in San Francisco, California, is known as the world's largest Leather Fair, an event marked by participants dressed in outrageous leather, rubber, and fetish attire. Over 300,000 people come to San Francisco for the Folsom Street Fair - making it one of the largest public events in California. The event caps off Leather Week - a seven-day event spotlighting leather and kink. Each year, the week before Folsom Street Fair is filled with motorcycle rides, the Leather Walk, special events, sex parties and other activities.