Sergei Mironovich Kirov was a Soviet politician and Bolshevik revolutionary whose assassination led to the first Great Purge.
Kirov was an early revolutionary in the Russian Empire and member of the Bolshevik faction of the Russian Social Democratic Labour Party. Kirov became an Old Bolshevik and personal friend to Joseph Stalin, rising through the Communist Party of the Soviet Union ranks to become head of the party in Leningrad and a member of the Politburo.
On 1 December 1934, Kirov was shot and killed by Leonid Nikolaev at his offices in the Smolny Institute for unknown reasons; Nikolaev and several suspected accomplices were convicted in a show trial and executed less than 30 days later.
Wikipedia https://en.wikipedia.org/wiki/Sergei_Kirov
Address 14 Кировская улица, Нижний Новгород, Russia
Coordinates 56°17'19.172" N 43°54'51.101" E