Diderot shows you the nearest unphotographed Wikipedia article to you, along with the distance and direction. You'll also get a notification whenever you're near an unphotographed location that is new to you.

Diderot uses the articles-by-lat-lon-without-images tool on wmflabs.org to find unphotographed articles. Only articles with .jpg images — not .png or .svg illustrations — count as illustrated, so you can photograph places that have only maps or diagrams.

Your location data updates every minute from your phone's geolocation.