Established in 1922 by Jean Massart (1865-1925), professor of botany at the Université Libre de Bruxelles (ULB), the original part of the garden was designed by landscape architect Jules Buyssens. This includes the Ethological Garden where Massart aimed to create a kind of botanical Belgium in miniature, featuring vegetation from the country's main natural habits: beach, wet meadow, marshland, pond edges, areas of limestone and sandstone rock, heathland, and sunny and shady hillsides. From the 1960s onwards, the site evolved naturally and most of the plants gradually gave way to flora typical of the Brabant marshes. Today, this living museum on the edge of the Sonian Forest includes nearly 2,000 species. They are presented in thematic collections: medicinal and aromatic plants, an arboretum of exotic tree species, a garden showing the evolution of flowering plants, cultivated plants and an orchard. There is also a wetland nature reserve forming part of the Natura 2000 network. (Listed 29/05/1997)