By Moscow's "Wall of Grief" - a memorial to the victims of Stalin-era political repression - I watch Russians laying roses and carnations, and lighting candles in memory of the opposition leader. Police are out in force, hurrying people along. In a country where dissent has pretty much been silenced, for many here just laying flowers is an act of courage. There is a palpable sense of disbelief. "I saw the news on my phone," Mikhail tells me. "My first reaction was, 'It's just a joke. It can't be real.' But then the news came more and more and more. And I was crying for one hour."