This near-vertical photograph shows metropolitan San Diego. A city of more than 2.5 million people, San Diego boasts one of the world’s great natural harbors. San Diego Bay, where the harbor facilities are located, is 12 miles (19 kilometers) long and up to 3 miles (5 kilometers) wide. The city is an important port of entry, home of numerous military and naval installations, and headquarters for the 11th U.S. Naval District. In addition to being a major retirement area, San Diego is a center for scientific research; major industries include aerospace, electronics, and shipbuilding. Sporting goods, clothing, rugs, furniture, and office equipment are manufactured, and tuna fishing and canning are important industries. The city has a delightful year-around climate, ocean beaches, and many historic sites, as well as a strategic location—only 12 miles (19 kilometers) north of the Mexican border. These attractions draw hundreds of thousands of visitors each year. The northern portions of Tijuana, Mexico, are visible south of San Diego.