Once a year for nearly a century, the hilly streets of San Francisco shut down for Bay to Breakers, a seven-mile race from the Embarcadero to Ocean Beach. Traditionally, however, Bay to Breakers has transformed into a debaucherous day of drinking and costumes that gives thousands of revelers a reason to rise and shine early Sunday morning.

San Francisco’s straight guys have made it their version of gay Pride by donning bright colors, body paint, tiny underwear and not much else, while the girls recycle slutty Halloween by putting on outlandishly sex costumes inspired by Katy Perry and other counter revolutionaries.

On Sunday, nearly 50,000 folks participated in the 2012 B2B. Drinking in public is been officially condemned by authorities, but there’s power in numbers and the city has become accustomed to the street-corner dance parties, the stumbling nudists and red cups galore.

Click through to see some fun times from Bay to Breakers 2012.

Photo credits: sylvainkalache, Seg Fault, David W Oliver, captin_nod, keved