San Francisco is a chief tourism destination in America, and its local economy is primarily based on service and technology. The San Francisco Bay Area dominates news headlines because it is an integral part of Silicon Valley. In sports headlines, San Francisco contributes teams like the Giants. San Francisco was also key to legal headlines because it was a city central in the legalization of gay marriage. Technology celebrities from San Francisco include Twitter, Salesforce, and AirBNB. San Francisco has been the setting of many popular movies such as Howl and Dirty Harry. San Francisco is often part of weather headlines due to its unique microclimates and earthquake-related emergencies.