MapComplete is a website where one can see and contribute to thematic maps. It show features within one topic (for example: public bicycle pumps). If a bicycle pump is selected, one sees more information about it and can answer some questions to help the community. If a bicycle pump is missing on the map, one can easily add this. There are plenty of maps available, each centered around a different topic (for example: playgrounds, public toilets, shops, public bookcases, waste containers and a map linking to the wikipedia article of the person/item a street is named after). All data comes from (and is added to) OpenStreetMap, so improving via MapComplete will also improve OsmAnd, Organic Maps and thousands of other applications.