Russian President Vladimir Putin arrives to attend an opening ceremony of a monument to the Governor General of Moscow between 1891 and 1905, Grand Duke Sergei Alexandrovich of Russia, in Moscow's Kremlin on May 4, 2017. Targeted by the Social Revolutionary Combat Organization, Grand Duke Sergei Alexandrovich of Russia was assassinated by a terrorist bomb at the Kremlin. / AFP PHOTO / POOL / Pavel Golovkin