On Friday morning, Russian prison authorities announced the death of Russian opposition leader Alexei Navalny. He reportedly had felt unwell after a walk in the courtyard of Penal Colony No. 3—where he had been transferred a few weeks earlier—and lost consciousness. Arriving rescuers’ attempts to revive him were unsuccessful, and Navalny’s team confirmed his death the following day. Though the exact cause of his demise is still unknown—Navalny’s allies have already said he was murdered—there is no doubt the Kremlin bears full responsibility.

People have gathered around the world in recent days to express their grief and anger over Navalny’s death. These gatherings have been small in Russia itself—the state is, per usual, cracking down on protest—but there will be an enduring image from this weekend: People laying flowers—at Navalny’s former home in Moscow, at the memorial for the victims of Soviet repression opposite the FSB headquarters, and in many other places throughout the country. These are acts of individual mourning, of silence, and of loneliness.