The central tribune for the Labor Day rally at Pаlace Square in Leningrad. Two photos.

The tribune was created by IZORAM artists and devoted to 'Soviets revolutionary struggle against world capitalism'. IZORAM made the design for October celebration in 1931 and Labour Day in Leningrad both in 1931 and 1932. The last design was devoted to the fight of communsit China against imperailist Japan including Shanghai incident. The celebrations were happened on former Palace square, renamed to Uritsky square in 1918.
The leader of IZORAM group in Leningrad Moisei Solomonovich Brodsky (1896-1944). He studied at Grekov Odessa Art school and started as cubist.
IZORAM (Mass Organization of Komsomol Amateurs Art) appeared in 1925 in Leningrad as the Association of Visual Arts Groups for Young Workers to develop a new, avant-garde language of amateur arts and crafts, as amateurs artists used to imitate academic art. Worker's art groups (izoyadra) were led by professional artists which assured the high quality of the amateur IZORAM productions. The association was disbanded in 1932 after the formation of the Artists Union.
The detailed description of this tribune with four images was published in Ioffe A. Novyi stil' [The new style]. Moskva-Leningrad, 1932, pp. 136-151.