Moscow's New Arbat Avenue is lined with some of the biggest video screens in Russia.
Today they're all displaying the same giant image: a burning candle and the Russian word "Skorbim" ("We mourn.")
Russia is mourning the victims of the Crocus City Hall massacre. There is no final death toll. The search for bodies continues.
Across the country the Russian tricolour is flying at half mast, entertainment and sports events have been cancelled, TV newsreaders are wearing black.
It might not be in the centre of Moscow, but Crocus City Hall is one of the most prominent music venues in Russia.
But Friday's bloodbath turned a concert hall into hell. The attackers killed not only with bullets, but with fire. They set the building alight and created an inferno. Video released by Russia's Investigative Committee shows that the roof collapsed. Metal beams, too.
Outside the building the police lines are still in place. From where I'm standing, I can see a single burned-out section of the entertainment complex. It's a hint of the devastation inside.
People are queuing to lay flowers at a makeshift shrine to the victims of the atrocity. The mountain of tributes is growing ever larger. As well as leaving roses and carnations here, visitors are placing dolls and soft toys on the flowers. That's because among the dead were children.
People have been leaving messages, too. One is addressed to the attackers:
"You are scum. We will never forgive you."
Among the crowd here there is a mixture of grief and anger.
"The country's heart is aching," says Tatyana, who's brought some flowers to lay here. "My soul is crying. Russia is crying. So many young people were killed. It feels as if my own children have died."
"It was a big shock," says Roman. "I live nearby, and I saw what happened from my window. It's horrific and a big tragedy."
"Whoever carried this out, they are not human. They are our enemies," a pensioner called Yevgeny tells me. "I think we should cancel the moratorium on the death penalty. At least for terrorists."
The Islamic State group has claimed it was behind the mass shooting at Crocus City Hall. It has released graphic images of the attackers on the rampage. US officials have said they have no reason to doubt that claim of responsibility.
The reaction here has been very different.
Russian officials have been promoting the idea that, somehow, in some way, Ukraine was behind the brutal attack.
In his TV address on Saturday, Russian President Vladimir Putin claimed that the four gunmen had been arrested trying to flee to Ukraine. He alleged that "a window had been prepared for them on the Ukrainian side to cross the border."
Kyiv has dismissed such suggestions. That hasn't stopped pro-Kremlin commentators from echoing claims of a Ukrainian connection.
On its website the pro-government newspaper Moskovsky Komsomolets has published a rabidly anti-Ukrainian opinion piece. Entitled "Ukraine must be declared a terrorist state", the article reached this conclusion: "It's time to destroy the Kyiv regime… all that gang must die. Russia has the resources to do this."
Which raises a key question. How will the Kremlin react to this devastating attack? Is Russia's leadership planning to use what happened at Crocus City Hall to justify a possible further escalation in Russia's war in Ukraine?
