https://commons.wikimedia.org/wiki/Category:Media_with_geo-coordinates_needing_categories has 35k files with geo-coordinates but without categories. Write tool to categorize those and future similar images. One idea is to use one of Reverse Geocoding websites, like https://developers.google.com/maps/documentation/javascript/examples/geocoding-reverse as an engine. Can be possibly written as a python bot, javascript, lua module (maybe ?), or service running on Tool_Labs.

See https://commons.wikimedia.org/wiki/Commons_talk:Geocoding#Category:Media_with_geo-coordinates_needing_categories_cleanup discussion.

Proposed Google-Code-In-2015 task