international workers' olympiads were more than just a games for the top athletes. the festival was based on a mass participation, it did not restrict entry on the grounds of sporting ability. 1931 workers' summer olympiad in vienna was the largest event with the participation of 100,000 athletes from 26 countries. the vienna workers' olympiad attracted some 250,000 spectators. it was much bigger event than the 1932 summer olympics at los angeles, both in number of participants as well as spectators. praterstadion (now ernst-happel-stadion) was constructed between 1929 and 1931 for the 1931 olympiad. the last workers' olympiad at antwerp in 1937 was a joint event with the red sport international organized spartakiads.