Nearly 16 million people make their way to San Francisco each year, making it one of the most popular vacation cities in the U.S.

The actual city of San Francisco extends about 47 square miles (122 square kilometers).

The city of San Francisco was built over an area with 43 hills, which makes driving around the city a bit of a challenge.

The Golden Gate is where the San Francisco Bay meets the Pacific Ocean. Crossing this opening is the world-famous Golden Gate Bridge.

The highest hills in San Francisco, Twin Peaks, are 900 feet (274 meters) above sea level; from atop these hill you can enjoy a magnificent view of the city.

We often think of summer as starting when school lets out, but in San Francisco it's quite cool in July. If you want to enjoy the summer weather, visit between late August and late October.

There are three airports in the area, but the main one is San Francisco International Airport. Even Mineta San Jose, however, is only an hour away.

If you want to get from San Francisco International Airport to the heart of the city by cab, expect to pay between $40 and $50.

The Bay Area Transit System (BART) is the easiest way to get into the city from San Francisco International Airport.

The cost of a BART ride is based on starting and ending points, but the range is rather affordable -- from $1.40 to $7.

San Francisco is famous for its cable cars -- they are a national landmark.

The cable cars of San Francisco may be a national landmark, but they cost five dollars per ride! There are several types of passes available, in case you want to ride the cable cars often.

The Bay Bridge is currently under construction, which means you might not be able to cross it when you'd like. Check the official Web site to find out whether the bridge is open.

In early February a parade makes its way through China Town in celebration of the Chinese New Year; it's one of the highlights of San Francisco's calendar.

The annual Cherry Blossom Festival is held in an area of San Francisco known, appropriately enough, as Japan Town.

The San Francisco 49ers were named after the pioneers who came to California in 1849 searching for gold.

The prison at Alcatraz Island, often referred to as The Rock, is one of the most popular tourist stops in the area.

At just over 1,000 acres, Golden Gate Park is one of the largest parks in any major city.

Presidio Golf Course is one of many world-class golf courses designed or renovated by the legendary Arnold Palmer.

Located on the San Francisco Bay, the city is often called "The City by the Bay."