Radio Day or Communications Workers' Day (as it is officially known in Russia) or Radio and Television Day is a commemoration of the development of radio in Russia. It takes place on May 7, the day in 1895 on which Alexander Popov successfully demonstrated his invention.
In 1895 Popov gave the first public demonstration of radio as a tool, using Sir Oliver Lodge's coherer, as a lightning detector before the Russian Physical and Chemical Society in St. Petersburg. Radio Day was first observed in the Soviet Union in 1945, on the 50th anniversary of Popov's experiment, and some four decades after his death.
Popov has generally been recognized in Eastern Europe as an "inventor of radio". Popov's works in the emission and reception of signals later publicized by Marconi by means of electric oscillations was carried out in 1893 by the engineer Nikola Tesla, before Marconi or Popov. Popov is still recognized in the Eastern European countries in contrast the West's recognition of Nikola Tesla and, historically, Guglielmo Marconi. Radio Day is still officially marked in Russia and Bulgaria.