In November 1975, an exhibition held in the second-year architecture studios at ETH caused an unexpected sensation. Tendenzen: Neuere Architektur im Tessin, curated by Martin Steinmann and designed by Tomas Boga, examined the recent projects of a group of mostly young architects from the Canton of Ticino. Reinstalled at EPFL in Lausanne only a few weeks later, and travelling to multiple other Swiss and European locations thereafter, Tendenzen is now known as one of the most influential architecture exhibitions of the 1970s. Fifty years after the original event, Tendenzen at 50: Portrait of an Exhibition, curated by Irina Davidovici and Frida Grahn, retraces its origins, impact, and afterlife. Drawing on archival materials, the majority of which are shown in public for the first time, it highlights not only the information that the exhibition conveyed, but also the hidden mechanisms it used for this communication, and crucially, the original materials it excluded.