The extension for the Royal Academy of Art in The Hague consists of an additional rooftop construction on top of the young national monument (Buys en Lurssen, 1936). It is an entirely transparent volume, consisting of steel and glass. The storey-high windows offer a view on the ministries, the historical centre and the art academy’s courtyard. The use of smart installation-engineering and moveable walls renders the interior flexible to use for various functions like education, exhibitions of students’ work, office spaces. Furthermore, the construction is designed to be light and reversible, which means the rooftop construction could be dismantled in the future without affecting the original national monument.