One of the largest building schemes of the century in Japan, the Tokyo Forum comprises a total floor area of 145,000 m2 and provides space for various activities, ranging from theatre, concerts and exhibitions to conferences and trade fairs. The forum skilfully exploits the triangular site, establishing a clear urban structure. A pedestrian route across the site expands into a landscaped plaza, to the west of which are four, clearly legible auditoriums of different sizes, clad in aluminium and granite. The most striking structure of the scheme, however, is the huge lens-shape glass hall, 210 m long and 58 m high, which serves as an exhibition space and as a foyer for all the auditoriums. The roof of the hall is supported by two enormous columns tapering at both ends and made up of welded hollow steel sections. The façade is a self-supporting structure. A flexible joint between the façade and the roof ensures that vertical movements in the latter are not transmitted to the glazed walls. The entire structure is designed to withstand earthquakes.