Moscone Center is the largest convention and exhibition complex in San Francisco, California. It comprises three main halls: Two underground halls underneath Yerba Buena Gardens, known as Moscone North and Moscone South, and a three-level Moscone West exhibition hall across 4th Street. It was initially built in 1981 by architects Hellmuth, Obata & Kassabaum as one single hall, Moscone South, and named after San Francisco former mayor George Moscone, who was assassinated in November 1978.