Northern California's best-known metropolis was once known as the “City of Flags” — a fitting moniker given the diversity of people who make up San Francisco's population. All those different cultures have swirled together to create a unique cosmopolitan experience, with everything from streetcar rides to Chinatown parades. Even the city's darkest historical corners, including Alcatraz prison, are now popular tourist destinations that you can enjoy with the entire family.