Short answers, pulled from the story.
Emperor Alexander II died in March 1881 after being killed by a bomb thrown by members of the People's Will group. This event marked one of history's first political terrorism campaigns targeting civilians to incite rebellion.
The Red Terror campaigns occurred during the Soviet era and targeted the population using hostage-taking tactics. Historians note that terrorist tactics were widely used by Soviet secret agencies against civilians within the country's borders.
Forty to fifty armed Chechens seized the Dubrovka Theater in Moscow on the 23rd of October 2002 trapping eight hundred fifty hostages inside. The siege ended with at least one hundred seventy deaths among the captives.
An Airbus A321-231 operating flight 9268 disintegrated above northern Sinai on the 31st of October 2015 killing all two hundred fourteen passengers and crew members. Islamic State of Iraq and the Levant claimed responsibility for the crash via Twitter and video statements.
Former FSB officer Alexander Litvinenko asserted that Russian apartment bombings were false flag attacks perpetrated by the FSB. Historians Amy Knight and Karen Dawisha supported claims that security services orchestrated attacks to legitimize military resumption in Chechnya.