One of the featured, huge paintings on display was "Prospectors Writing a Letter to the Creator of the Great Constitution" completed 1937. The "Creator" of that marvelous, idealistic and fraudulent constitution was Josef Stalin, of course.
Its painter was Vasily Nikolayevich Yakovlev (1893-1953), background here, not to be confused with the Vasily Yakovlev (biography here) who was liquidated by Comrade Stalin in a 1938 purge.
What I find interesting is that Yakovlev, consciously or otherwise, borrowed the theme of the famous painting "Reply of the Zaporozhian Cossacks to Sultan Mehmed IV of the Ottoman Empire" (Wikipedia entry here) by Ilya Repin (1844-1930), painted over the years 1880-1891.
The letter Repin dealt with was negative in tone and that of Yakovlev was positive, which explains difference in body languages of the subjects.
Images are below. Click on them to enlarge.
One measure of how large this painting is can be seen with reference how close to the floor it had to be hung.