At least 133 people were killed in the attack on Crocus City Hall near Moscow. The rock group Piknik was actually supposed to perform at the sold-out concert.
There have been a number of deadly explosions and bombings in the country in recent decades, with the Russian government often blaming Chechen separatists. In spring 2017 it will hit the Saint Petersburg subway, with an Islamist terrorist group from the North Caucasus again claiming responsibility for the attack. An (incomplete) chronicle of terror: Moscow Again and Again.