On 7 August, 2008, fighting in Georgia's breakaway region of South Ossetia escalated into war between Georgia and Russia.
The death toll is generally put in the hundreds. Villages, towns and the South Ossetian capital Tskhinvali were largely destroyed. Tens of thousands of people were forced to flee their homes.
A year later, we recall the causes of the conflict and assess what is happening now.
What is the current political situation?
Russia has recognised South Ossetia, and Georgia's other breakaway region, Abkhazia, as independent states. It stations troops there to guarantee their safety and to guard the boundary with the rest of Georgia.
Georgia insists the two regions remain part of its sovereign territory. Apart from Russia, the rest of the international community overwhelmingly take this view.
Therefore there is political and diplomatic stalemate.
What is happening on the ground?
Russian troops have effectively sealed the boundary between South Ossetia and the rest of Georgia. On the Georgian side, about 225 EU monitors patrol to try to check implementation of the ceasefire and help stabilise the situation.
Since Russia forced UN and OSCE observation missions in Georgia to pack their bags, the EU Monitoring Mission (EUMM) is the only body doing the job.
In the week leading up to the anniversary, both sides have accused each other of breaching the ceasefire terms.
Russia accused Georgia of firing mortars into villages in South Ossetia. It said Georgia was preparing for a new conflict.
Georgia said Russian troops had been moving border posts in order to seize more Georgian land.
EU monitors said they could not find evidence of either claim. Analysts say both sides are ramping up the rhetoric for their own political ends.
There have been flashpoints along the boundary. In June an ambulance driver was killed, and before that a Georgian police officer, by mine explosions.
In a report in June the International Crisis Group (ICG) referred to "a dangerous atmosphere in which extensive fighting could again erupt".
But EUMM spokesman Steve Bird tells BBC News the number of violent incidents has fallen dramatically recently, and that talks and agreements with the parties in Abkhazia and the Georgian authorities have helped gradually build trust.
The incidents, he says, "are unrelated, not part of a pattern or trend. The overall position is broadly stable, though it is unpredictable".
Have ceasefire terms been met?
A six-point ceasefire plan agreed on 12 August, 2008, five days after the war broke out, and an EU-brokered agreement in September, specified that Russian forces should return to their pre-conflict positions and levels.
According to many observers, that has not happened. While Russia has withdrawn from most of the Georgian-controlled territory, it remains in some areas.
The EUMM says Russia is in breach of the boundary near the checkpoint at Perevi in the west of South Ossetia.
"The Russians admit they're just inside Georgian territory, and say it is because Georgian police have moved there in too great numbers," said spokesman Steve Bird.
He also says the Russians are in breach in Akhalgori in the east, a part of South Ossetia that was previously in Georgian hands, and so should have reverted to Georgia post-ceasefire.
Russia denies being in breach in Akhalgori. It cites "new realities" - ie its recognition of independence for South Ossetia and Abkhazia.
What triggered the crisis?
The separatist administrations in South Ossetia and Abkhazia have been trying to gain formal independence since breaking away in the early 1990s.
Tensions in both regions began to escalate after Mikheil Saakashvili was elected Georgian president in 2004, on a promise to reunite the country.
The conflicts had remained largely frozen, despite occasional flare-ups, before August 2008.
A series of clashes between Georgian and South Ossetian forces in the summer of 2008 prompted Georgia to launch an artillery bombardment and ground attack on South Ossetia on 7 August.
Georgian forces controlled the South Ossetian capital, Tskhinvali, for part of the following day.
Russia, meanwhile, poured thousands of troops into South Ossetia, and launched bombing raids both over the province and on targets in the rest of Georgia.
There have been reports of war crimes on both sides.
Did the Russian forces enter South Ossetia before or after the Georgian attack?
This is unclear.
Several days after fighting began, Georgia said it began its assault after learning that a large convoy of Russian armour was coming through the Roki tunnel, from North Ossetia into South Ossetia.
Russia says it acted to defend Russian citizens in South Ossetia, and its own peacekeepers stationed in the breakaway region.
How did the conflict develop?
Russian forces occupied parts of Georgia adjoining South Ossetia, including the town of Gori, a strategic town on the main road linking eastern and western Georgia.
They also moved from bases in Abkhazia into parts of western Georgia, and the Russian fleet went into action against the Georgian navy.
Abkhaz forces recaptured the Kodori Gorge - a region of Abkhazia taken by Georgian troops in 2006.
Who were the main casualties?
Large numbers of civilians were driven out of their homes in South Ossetia. Many South Ossetians crossed over to the Russian republic of North Ossetia.
Residents of Georgian villages in South Ossetia, and the town of Gori, also fled. Around 22,000 are estimated still to be living in limbo in Georgian camps.
The heavy fighting left the South Ossetian capital, Tskhinvali, largely in ruins.
Overall, the UN says about 133,000 people were displaced by the hostilities and many have returned home since the ceasefire.
Why was Russia involved?
More than half of South Ossetia's 70,000 citizens were said to have taken up Moscow's offer of Russian citizenship, prior to the conflict. Russia says its actions were designed to protect those citizens.
Russia also had peacekeepers based in South Ossetia. Some of these were killed in the Georgian attack on 7 August.
Before the war, Russia said it respected Georgia's territorial integrity, and only wanted to look out for Russian citizens.
But, following Georgia's military action, Russia recognised the independence of both South Ossetia and Abkhazia on 26 August.
The move was roundly condemned by Western nations. Only Nicaragua has joined Russia in recognising the regions.
What about Nato, and energy?
Russia has made no secret of its opposition to President Saakashvili's plans to take Georgia into Nato, and some analysts believe Russia's military action was intended to head this off.
Nato countries have since gone cooler on Georgian entry, though they say it is still a goal.
Western Europe is trying to diversify its energy sources so as not to rely too heavily on Russian oil and gas. To this end, at least two pipelines carry oil from the Caspian to the West via Georgia.
The conflict last year made investors nervous about the security and future viability of such projects.