The San Francisco Bay Area, commonly known as the Bay Area, or the Bay, is a metropolitan region that surrounds the San Francisco and San Pablo bays in Northern California. The Bay Area encompasses the metropolitan areas of San Francisco (12th largest in the country) and San Jose (31st largest in the country), as well as four other smaller, surrounding metropolitan areas. When defined as a Combined Statistical Area, the Bay Area is the sixth largest in the country, including over 7.2 million people. Overall, the Bay Area consists of nine counties, 101 cities, and 7,000 square miles. The Bay Area hosts many cities, towns, military bases, airports, and associated regional, state, and national parks, connected by a massive network of roads, highways, railroads, bridges, tunnels and commuter rail. The combined urban area of San Francisco and San Jose is the 46th largest urban area in the world. San Francisco is the financial center of the Bay Area (and has the second highest population density in the nation after New York City), while San Jose is the center of Silicon Valley and the most populous city. The Bay Area is renowned for its natural beauty, liberal politics, affluence, diversity, and new age reputation.