In <a href="https://en.wikipedia.org/wiki/Saint_Petersburg" id="mwnw" rel="mw:WikiLink" title="Saint Petersburg">Saint Petersburg</a>, Russian scientist <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Alexander_Stepanovich_Popov" id="mwoA" rel="mw:WikiLink" title="Alexander Stepanovich Popov">Alexander Stepanovich Popov</a> demonstrates to the Russian Physical and Chemical Society his invention, the Popov <a href="https://en.wikipedia.org/wiki/Lightning" id="mwoQ" rel="mw:WikiLink" title="Lightning">lightning</a> detector—a primitive <a href="https://en.wikipedia.org/wiki/Radio_receiver" id="mwog" rel="mw:WikiLink" title="Radio receiver">radio receiver</a>. In some parts of the former <a href="https://en.wikipedia.org/wiki/Soviet_Union" id="mwow" rel="mw:WikiLink" title="Soviet Union">Soviet Union</a> the anniversary of this day is celebrated as <a href="https://en.wikipedia.org/wiki/Radio_Day" id="mwpA" rel="mw:WikiLink" title="Radio Day">Radio Day</a>.