The Aula, or assembly hall (1966), was designed by architects Van den Broek and Bakema and is the best example of Brutalist architecture in our country. The term refers to the various applications of concrete visible everywhere, best seen in the enormous basin of the auditorium with its polygonal columns. Despite its massive structure, the concrete roof seems to float on thin window strips. Beautiful spatial effects inside, with split-level central staircase stretching out over full height of the building. Building goes by nickname of ‘the frog’.