Long before the arrival of European administrations, the area that now forms the European Quarter was already undergoing transformation into an office district. Did the establishment of major European institutions intensify this phenomenon? Today, this tertiary district stands as an open-air museum of office architecture, from the 1960s to the present day. At a time when work and living patterns are evolving, large office districts invite us to reflect on their future: how can we reinvent these spaces? Through the exploration of the history of the quarter and its iconic buildings, with examples and counter-examples, we will address topics such as the evolution of office buildings, their preservation, repurposing or conversion, and the concept of heritage-making. Come and discover how the past and present of these buildings can inspire innovative solutions for the future of this district!