Résumé : Chapter on the Mundaneum in the exhibition Institution Building at Civa (2021). Armed with the 3-by-5 inch index card and the Universal Decimal Classification (UDC) system, the Belgian encyclopaedist and internationalist Paul Otlet (1868-1944) undertook the utopian project of mapping the world of knowledge, and making it navigable. His ambitions went well beyond the enterprise of cataloguing all what had been published in a bibliographic repertory. After launching the concept of “documentation,” which had a major impact on bibliography and library science at the turn of the twentieth century, he made plans for a new type of knowledge institution: the “Mundaneum”. A library, university, laboratory, and interface to a ‘worldwide brain’ at the same time, the Mundaneum crystallized his belief in the unity and institutionalization of knowledge. This exhibition brings together a selection of his visualizations of the information society of the early 20th century, as he saw it, and is to be read against the background of the disunity of all practical endeavors to realize that dream at the different levels of science, culture and politics.