On November 2, 1937, five ruby stars lit up over the towers of the Moscow Kremlin. And since then, the unquenchable light has become part of the country's history and life. The best engineering and scientific minds of that time worked on creating stars. Many unique technologies had to be created from scratch and in a very short time, which was typical of the era of large construction projects. What discoveries were made, as well as what is the secret of the eternal and pure radiance of the Kremlin stars.