To open up the image archives of the Berlin Ethnological Museum to the public, the museum and Fraunhofer FOKUS developed the Tag.Check.Score. crowdsourcing app in the context of the Code for Europe initiative. The app is based on the idea of digital volunteer work. With the app, users can add metadata to the museum’s photos, correct existing tags and earn points doing so. The goal of Tag.Check.Score. is to develop an open-source solution that other museums, libraries and archives can also use to tackle similar challenges.