WOEID
A WOEID (Where On Earth IDentifier) is a unique 32-bit reference identifier, originally defined by GeoPlanet and now assigned by Yahoo!, that identifies any feature on Earth. In 2009, Yahoo! released GeoPlanet's WOEID data to the public, with the last release on 1 June 2012, after which Yahoo! decided to cease making the data downloadable until they "determine a better way to surface the data as a part of the service". WOEIDs are used by a number of other projects, including Flickr, OpenStreetMap, Twitter, WOEID Search Engine and Nations24. WOEID of some popular locations on Earth. From  WOEID Search Engine: Example. E.g. Berlin does not know about Germany, which itself doesn't know about Europe and so forth. GeoPlanet records, or places as they are called by Yahoo!, always (except one) have a reference to its parent place and therefore offer relations between places like the following: If you take e.g. our company's district you will get the following family tree: