Russia's biggest air strikes against Ukraine since the start of the war killed at least 19 people, drove thousands of Ukrainians back into air raid shelters and knocked out electricity in hundreds of towns and villages.
The strikes - denounced in the West for deliberately hitting civilian targets - have been hailed by hawks in Moscow as a turning point that demonstrates Russia's resolve in what it calls its "special military operation" in Ukraine.
But Western military analysts say the strikes came at a staggering cost, depleted a dwindling supply of long-range missiles, hit no major military targets and are unlikely to change the course of a war going badly for Moscow.
"Russia lacks the missiles to mount attacks of this sort often, as it is running out of stocks and the Ukrainians are claiming a high success rate in intercepting many of those already used," wrote Lawrence Freedman, emeritus professor of war studies at King's College London.
"This is not therefore a new war-winning strategy but a sociopath’s tantrum."
How are the attacks portrayed in Russia?
President Vladimir Putin described the strikes as a response to what he called terrorist attacks by Ukraine, including a blast on Sunday that damaged Russia's bridge to Crimea, which it built after annexing the peninsula it seized in 2014.
Hawks in Russia had been demanding for weeks that Putin escalate the conflict, and many of them hailed Monday's attacks.
Ramzan Kadyrov, the Putin loyalist leader of Russia's Chechnya region who had lately called for military commanders to be sacked, said he was now 100% behind the strategy.
Margarita Simonyan, head of RT, Russia's state-run overseas media channel, said Moscow had been waiting for the perfect time to demonstrate its strength. Quoting a proverb, she tweeted: "A Russian harnesses his horses slowly but drives them quickly."
Dmitry Medvedev, deputy head of Putin's advisory security council, said Russia would now be able to widen its objectives: "The goal of our future actions, in my view, should be the complete dismantling of the political regime of Ukraine."
Can Russia keep this up?
Ukraine says Russia fired 83 cruise missiles on Monday and that it shot down at least 43 of them. Moscow says it fired more than 70 and all its targets were hit. Both sides say the attack was on a huge scale, unseen at least since Russia's initial wave of air strikes on the first night of the war in February.
Each Kalibr cruise missile is estimated to cost more than $6.5 million, meaning Moscow fired around half a billion dollars worth of missiles in a single day.
Western military analysts have no firm figures for how many missiles Russia has left, but for months have pointed to indicators suggesting the supply is limited.
As far back as July, Joseph Dempsey and Douglas Barrie of the International Institute for Strategic Studies noted that Russia was increasingly using anti-ship missiles to strike targets on the ground. This "suggests that Moscow is having to muster its remaining conventionally armed land attack cruise missile resources more carefully," they wrote.
Can Ukraine protect itself?
President Volodymyr Zelenskyy said securing more air defences for Ukraine is his number one priority. Western leaders including U.S. President Joe Biden have promised more systems, though it takes time to deliver them.
Ukraine now relies on Soviet-era air defence systems such as the S-300. Washington promised several months ago to send its sophisticated NASAMS system, but said in late September that delivery was still around two months away.
In practice, military experts say Ukraine will probably never be able to defend its entire land area - the second largest in Europe after Russia itself - from attacks on scattered low-priority targets.
Air defences, such as the U.S. Patriot missile system, are designed mainly to protect specific, high priority targets. Others can provide broader protection but over a comparatively small area, such as Israel's vaunted "Iron Dome" system which protects a country around one twentieth the size of Ukraine.
"Bottom line: Just like it was difficult to stop Saddam from launching SCUDs, and as much as we want to help Ukraine, it's challenging to completely counter all Putin's war crimes that unfortunately include launching missile strikes against civilian targets," tweeted Mark Hertling, a former commander of U.S. land forces in Europe.
Still, Monday's attacks appear to show that Ukraine is already far from defenceless. While Kyiv's claim to have shot down more than half of the missiles is impossible to verify, Russia did not hit any targets with the highest strategic value, such as leadership buildings in the capital, which are likely to have been best protected.
What's next?
Russia still faces the same strategic difficulties it did before Monday's attacks: demoralised and poorly equipped forces spread along a 1,000-km frontline, with long supply lines vulnerable to Ukrainian attacks.
Russia's initial advantages, above all the massive firepower of its artillery, allowed it to destroy and capture cities in May-July. But since September, its artillery-heavy forces have proven a poor match for defending occupied territory from mobile and increasingly well-equipped Ukrainian units.
Moscow still lacks control over Ukrainian air space, which would allow for the intensive strikes by jet and helicopter that helped it defeat rebels in Syria and Chechnya.
Ben Hodges, another former commander of U.S. ground forces in Europe, said that despite Monday's attacks, Ukraine still appeared to have "irreversible momentum" on the battlefield.
"Russia's logistics system is exhausted and no Russian wants to fight in Putin's war in Ukraine," he tweeted.