It is a century since the execution of Russia's last tsar and his family after the revolution that established the Soviet Union, a massacre that still raises questions today.
Here is a look back at the secret shooting of Nicholas II, his wife and five children in July 1918 and Russia's efforts since then to come to terms with the killings.
- Revolution -
In February 1917, at the height of World War I, desperation at troop losses and food shortages caused mass rioting in the imperial capital Petrograd, today called Saint Petersburg.
The revolt escalated and thousands joined, leading Nicholas II to deploy the army. But the soldiers mutinied and the little-loved tsar abdicated in March.
His departure brought the curtain down on the Romanov dynasty that had ruled Russia for 300 years.
A fragile provisional government took over but was quickly overthrown by Vladimir Ilyich Lenin's Marxist Bolsheviks and the Soviet Union was created.
- Shot in a cellar -
Nicholas sought asylum, including in Britain where King George V was his first cousin, but was rejected.
The family and a handful of aides were arrested and moved to Siberia and then to Yekaterinburg, far from the seat of power.
When anti-Bolshevik "White" Russian forces approached, local authorities were ordered to prevent a rescue.
In the early hours of July 17, 1918, Bolshevik police ordered the prisoners to the cellar of the house where they were being held.
There the head of a squad of secret police, Yakov Yurovski, announced an order had been issued for their execution.
"Nicholas turned and, astonished, tried to ask a question. Yurovski repeated his statement and, without hesitation, shouted: 'Fire!'," historian Robert Service recounts in "The Last of the Tsars" (2017).
Nicholas, his German-born wife Alexandra, their five children -- aged from their early teens to early 20s -- were killed, along with a maid, cook, valet and doctor.
By some accounts it was a bloody and brutal scene.
"The first bullets did not bring death to the youngest ones and they were savagely killed with blows of bayonets and gun-butts and with shots at point-blank range," says the Russian Orthodox Church, which regards the family as martyrs, on its website.
The bodies were reportedly hastily buried in an unmarked grave on the outskirts of Yekaterinburg.
- Discovery, 60 years later -
The remains of Nicholas, his wife and three of their daughters -- Anastasia, Olga and Tatiana -- were tracked down by two amateur historians in 1979, although the discovery was only revealed in 1991, in the dying days of the Soviet Union.
Exhumed and identified, they were buried in the imperial tomb in Saint Petersburg in July 1998 in a grandiose ceremony attended by president Boris Yeltsin.
The execution was "one of the most shameful pages in our history", the result of "an irreconcilable divide in Russian society," Yeltsin said.
Amid popular legend that one of the children may have survived, several pretenders claimed later to be Anastasia, some seeking access to the royal fortune. They were always dismissed by the authorities.
Bone fragments were found in 2007 that investigators and geneticists have said are from the two remaining children, heir Alexei and his sister Maria.
But the powerful Orthodox Church doubts their identity and the remains lie in boxes in state archives, attempts to rebury them stalled.
The Church in 2000 accorded the entire family the status of martyrs because of their faith.
- Was Lenin responsible? -
In 2008 Russia's Supreme Court formally rehabilitated Nicholas II, declaring that he and his family were unlawfully killed by Soviet authorities.
But a long-running investigation into who was responsible closed in 2011 without finding evidence that Lenin had himself ordered the execution.
It nonetheless apportioned him some blame for approving the killings and not punishing the executors.
There is "no reliable document proving the instigation of Lenin" or his regional chief Yakov Sverdlov, a top investigator said in an AFP story at the time.
However, "when they heard that the whole family had been shot, they officially approved the shooting," the investigator said.