San Diego San Diego, named after Saint Didacus, is the second-largest city in California and the eighth largest city in the United States. Though San Diego’s economy is multifaceted— biotechnology, defense manufacturing, agriculture, software development and microbreweries are some of the city’s biggest moneymakers— tourism is a cornerstone that can’t be ignored. Tourism drastically affects the city’s culture, and San Diego houses many local attractions, such as SeaWorld San Diego, Belmont amusement park, San Diego Zoo, San Diego Zoo Safari ...