RECLUS (RĂ©seau d'Ă©tude des changements dans les localisations et les unitĂ©s spatiales) is a public interest group founded in 1984, associated to the Maison de la gĂ©ographie de Montpellier (Geography House of Montpellier). The acronym translates to "Network for the study of changes in the locations and the spatial units" and was coined as a tribute to ĂlisĂ©e Reclus, the 19th-century French geographer, author of the New Universal Geography, a treatise in 19 volumes, published by Hachette, between 1876 and 1894 [1]. One of the most important ideas of Reclus is indeed the trans-boundary region, which is retaken by Roger Brunet, the founder of the RECLUS group and its director until 1991, in order to formulate the concept of the European Megalopolis. HĂ©rvĂ© ThĂ©ry was a Director of the institute