Hilly San Francisco is America's 13th-largest city. Three other California cities - Los Angeles, San Diego and San Jose - are larger. Yet each year, San Francisco ranks first or second in the nation in tourist visits.

What's the attraction? Why did singer Tony Bennett, in his signature song, leave his heart in San Francisco, rather than, say, Boston or Cincinnati?

Perhaps it's the setting; the city is shrouded in fog along 40 steep hills overlooking glistening San Francisco Bay. Many of the densely-packed neighborhoods clinging to these hills are filled with ornate Victorian houses called "painted ladies."

Carol M. HighsmithA San Francisco cable car - the nation's only moving national monument, ascends hilly Hyde Street.

Considering its ocean beaches, bustling commercial waterfront, two of the world's most striking bridges, and the largest urban park west of Philadelphia, it's no wonder San Francisco is a desirable - and expensive - place to live and a treat to visit.

Add in its lively theater scene, the oldest ballet company in the United States, dozens of art galleries, and thousands of fine restaurants, and San Francisco exudes sophistication.

The city does get a lot of rain, but its winters are mild and its summers cool. Really cool. In fact, there's a delightful saying - incorrectly credited to humorist Mark Twain - that the natives enjoy: "The coldest winter I ever spent was a summer in San Francisco."

Carol M. HighsmithIn the distance behind Coit Tower atop Telegraph Hill, lies the "inescapable" Alcatraz Prison. A few convicts escaped took their chances in the bay's icy waters. None is thought to have made it to shore.

Among the city's top visitor attractions is Chinatown - the largest Asian community outside Asia. And one of the enduring symbols of San Francisco is its fleet of 37 cable cars - the only ones of their kind remaining in the world.

San Francisco's hills themselves are tourist attractions - especially a serpentine stretch of Lombard Street that everyone calls the "Crookedest Street in America."

In the Haight-Ashbury neighborhood, you can still run into people who are trying to recapture the "hippie" experience of San Francisco's 1967 "Summer of Love." And in San Francisco Bay, Alcatraz Prison, which once housed the worst of the worst federal prisoners, is open for tours.

These unique allurements explain why the American short-story writer O. Henry wrote, "East is East, and West is San Francisco."