This page has information from the Wikipedia on San Diego available here.
San Diego is the eighth-largest city in the US and 2nd city in CA. It’s located on the coast of the Pacific Ocean in Southern California, immediately next to the border of Mexico. The birthplace of California, San Diego is known for its mild climate, natural deep-water harbor, extensive beaches, long association with the U.S. Navy, and recent emergence as a healthcare and biotechnology development center.
Historically home to the Kumeyaay people, San Diego was the first site visited by Europeans on what is now the West Coast of the US. When they landed in San Diego Bay in 1542, Juan Cabrillo claimed the entire area for Spain, creating the basis for the settlement of Alta California 200 years later. The Presidio and Mission of San Diego, established in 1769, were the 1st European settlement in what is now CA. In 1821, San Diego became part of newly free Mexico, and in 1850, became part of the US following the Mexican-American War and the admission of California to the union.
The city is the county seat of San Diego County and is the economic epicenter of the San Diego–Carlsbad–San Marcos metropolitan area as well as the San Diego–Tijuana metropolitan area. San Diego’s major economic engines are military and defense-related activities, tourism, international trade, and manufacturing. The University of California, San Diego (UCSD), with the affiliated UCSD Medical Center, has helped make the area a center of research in biotechnology.