This article aims to demonstrate how the exhibition form and content created a powerful dialectic in the Exhibition of the Building Workers Unions (Berlin, 1931). Interactive display techniques designed by Herbert Bayer, László Moholy-Nagy and Walter Gropius supported messages advocating the crucial societal and economic role played by construction-sector labour unions. Designed to promote the system of free trade unions in Germany, the show demonstrated the potential effectiveness of photography as an integral part of a didactic system, choreographed into various displays that combined images with dynamic graphics and informative texts. To foster interest in the material, the artists used audience-involving strategies including startling viewpoints, photo-strips mounted on moving laths, and touch stations that would beckon the viewer. Taken together, the techniques constituted one of the boldest inter-war attempts to stimulate viewers through multi-sensory empowerment, and incite collective awareness at a time of immense political stakes.If on previous occasions, the viewer marching past the picturewall was lulled […] into a certain passivity, now our design should make the man active. This should be the purpose of the [exhibition] room.