The Mapbox Geocoder Swift SDK provides address search and reverse geocoding in Swift or Objective-C on iOS, macOS, tvOS, and watchOS. The Mapbox Geocoding API provides geocoding and reverse geocoding, that is a way to turn your coordinates into addresses, or your addresses into coordinates. The geocoding API offers forward and reverse permanent geocoding that allows you to run batch queries, store the results, and use them on a Mapbox map or anywhere else. Mapbox is an open source mapping platform for developers that provides tools for Maps and location data, Location based games, VR and AR applications and more.
It's a little bit creepy, but it's also a little bit genius. Singles for Foursquare builds a dating and messaging service on top of the location-sharing application. The result is a mashup that could match up hip iPhone-using, Foursquare-playing, same-bar-going early adopters.
There are any number of questions that can be answered by Wikipedia, but you can add "where am I?" to the list. Given any latitude/longitude coordinates, the WikiLocation API will find you corresponding Wikipedia articles to tell you about your surroundings.