Android/iOS: Visiting a new city is an awesome holiday, but it can be overwhelming without a guide. Detour provides audio tours of major cities like San Francisco, New York and Austin to show you around town. The app currently features 10 separate guides for San Francisco, with free previews available for Austin, New York, London, Paris, Berlin, Barcelona and Marrakech. Chicago and Los Angeles are listed as "coming soon". Each tour shows you where to walk while narrating your surroundings. You can also sync your tour with other people so you can all listen together on your own devices.
The selection is a little sparse at the moment, but most of the preview tours are currently free. The San Francisco tours cost $7.99 each, or you can get the entire set for $38.99. That's not too bad when compared with other guided tour services you'll find in various cities.