May 18, 2012 3:40 pm Facebook IPO Day Mark Zuckerberg rings the Nasdaq’s opening bell from Facebook’s Menlo Park headquarters. US & World Videos 2:20 Cinco de Mayo parade and celebrations to bring road closures in San Jose 2:06 Clash at UC Berkeley protest encampment 0:35 Bay Bridge lights set to shine again in 2025 0:33 Livermore police search for suspect in double homicide 2:42 Forecast: Warm day, Saturday rain