The death of Alexei Navalny: Putin, like Stalin, kills because he can. It is almost a symbol of how the Kremlin autocrat understands power.
Navalny, a nationalist and defiant leader, was no longer a serious enemy for the Russian leader. He had been transferred to one of the prisons furthest from civilization, in the worst of Siberia. His death happens in the style of Joseph Stalin's bloody dictatorship, as a confirmation that the regime can do it and that's it.