To the north of the Theme Space was the Festival Plaza. This was a flexible space that contained a flat area and stepped terrace. The plaza could be rearranged to provide for different requirements for seating capacity, from 1500 to 10000. The flexibility extended to the lighting and audio visual equipment allowing for a range of musical performances and electronic presentations.[6] Festival Plaza was covered by the world's first large-scale, transparent membrane roof. It was designed by Tange and structural engineer Yoshikatsu Tsuboi + Kawaguchi & Engineers. Measuring 75.6 m in width and 108 m in length, it was 30 m high and supported by only six lattice columns.[7]
Seventy-seven countries participated in the event, and within six months the number of visitors reached 64,218,770, making Expo '70 one of the largest and best attended expositions in history. It held the record for most visitors at an Expo until it was surpassed by the Shanghai World Expo in 2010.