This is the third annual SVCC.
It's taking place at the San Jose Convention Center Friday through Sunday.
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Despite the gray and damp conditions, courtesy of the Pineapple Express, hundreds of enthusiastic attendees came in costume for the festivities.
They waited in line to meet celebrities like Jerry Mathers and Mads Mikkelsen.
But co-founder Rick White said Silicon Valley Comic Con is unique because it goes beyond celebrities and pop culture.
"We look at science fiction as tomorrow's science reality," said White.
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He pointed to special guests who will be hosting panel discussions, including Dr. Mae Jemison, the first female African-American astronaut.
So much to see and do and learn at SVCC... plus plenty of new friends to make!