The Auditorium was the world’s first two-level air-supported structure. With two sets of revolving doors, the ground level could operate at a higher pressure than the upper level. This was necessary to support the weight of people sitting on its ceiling, which was itself the upper-level floor.
The foyer on the ground level was circular, with transparent walls, and numerous sandbags held down its ceiling. The ceiling constituted a soft, air-supported floor for the upper level, which could be reached via a spiral staircase. Sitting on that air-cushioned floor, visitors could enjoy performances and talks that were given on a small stage in the centre (though this functionality was sometimes undermined by the audience's preference for wildly jumping around on the inflatable floor).
The upper floor of this structure had a yellow, air-supported, dome-shaped roof that could be removed to create an open-air theatre. Its emergency exits were simply zips in the wall and rope ladders that could unfurl down the outside of the ground-floor cylinder.