Wheelmap is a map for finding wheelchair accessible places. The map works similiar to Wikipedia: anyone can contribute and mark public places around the world according to their wheelchair accessibility. The criteria for marking places is based on a simple traffic light system: Green = Fully wheelchair accessible, Yellow = Partly wheelchair accessible, Red = Not wheelchair accessible, Grey=Unknown. Places that are not yet marked according to their wheelchair accessibility have a grey marker. They can be marked by anybody quickly and easily. The information that is collected in this way is easy to understand, available free of charge and can be shared freely. Wheelmap.org is based on the world map OpenStreetMap and shows 130 different types of places. These place types are illustrated by the icons in the green, yellow, red and grey markers.