San Diego: San Diego is a city located in the extreme southwest of the state of California (United States) and, therefore, in the extreme southwest of the continental United States. The county bordering Tijuana, Mexico. Capital of San Diego County, the city is famous for its mild climate and numerous beaches.
San Francisco: is a city in northern California on the West Coast of the United States. It is located on a peninsula full of hills that separates the San Francisco Bay from the Pacific Ocean. It is the fourth most populated city in the state with 776,773 inhabitants, while its metropolitan area than 7 million inhabitants, being not only the largest U.S. but worldwide, where thanks to the activity of Silicon Valley has pioneered the computer revolution.