We are Citizen Science! The orientation of the Topotheque to work together with the public in order to secure historical sources, which can also be used for scientific research, corresponds to the idea of what is known today as „Citizen Science“. We are therefore pleased that the Topotheque has become a member of ECSA, the European Citizen Science Associaton, in addition to membership of the Austrian platform “Austria forscht”. This non-profit association was founded in 2013 to promote the growth of projects and initiatives in Europe that involve public participation in scientific processes. ECSA currently has more than 200 members from over 28 countries and has developed from an originally informal network of researchers, key people and institutions working in the world of Citizen Science to a European reference network of CS initiatives. With this membership, the Topothek has entered a new network that enables new contacts not on the content but on the methodological level. We look forward to new suggestions and also to being able to support our projects with other like-minded projects.