No-one will ever know exactly where the 71 refugees and migrants from Iraq, Syria and Afghanistan died.
The grisly discovery of their bodies in the back of a lorry on an Austrian motorway last August sent shockwaves across Europe. One of the victims, Lida Rahm, was a baby, less than a year old.
They were part of a wave of migrants and refugees heading across the Western Balkans towards Germany and their deaths provided one of the catalysts for borders being opened to allow the influx through.
Europe's migrant crisis:
Although most of the bodies have been returned to their families, 13 have been buried at the Muslim cemetery at Liesing on the outskirts of Vienna.
It does not take long to find their graves: the cemetery was only opened in 2008 and is not very full. The graves all show the same final date: 27 August 2015.
Crammed into the back of the small Volvo meat truck, standing room only, the 71 could not have survived for long.
The lorry, emblazoned with pictures of sausages and a chicken's head, had been sealed airtight.
Police believe they may have suffocated within an hour of the lorry starting its journey at Roszke, on the Hungarian-Serbian border early on 25 August 2015.
At the wheel was a man named Mitko, a Bulgarian living in Hungary, with a long police record.
Why was the lorry sealed shut?
Mitko's usual driver was sick that day, so he decided to drive the lorry himself.
But he did not understand how to keep the doors only partially shut, in a way that air could still come in. When he set out from Roszke just before dawn for the 850km (530 mile) journey to Munich, he inadvertently sealed the migrants in.
This is the version of the story told by acquaintances of Mitko in Lom, his hometown, on the shore of the Danube in north-west Bulgaria.
Mitko, 29, started in the used-car business, first repairing, then driving minibuses of Bulgarians to workplaces in Western Europe.
Unpaid speeding fines and the loss of his licence, then a prison term for robbing a filling station, pushed him deeper into trouble. There was always money to be made smuggling cheap cigarettes across the Serbian border into Bulgaria.
When the influx of refugees and migrants gained momentum in 2014 and 2015, organised groups like the one Mitko was involved in shifted to human trafficking.
"Arabs in Turkey organise everything," a Bulgarian smuggler from a rival gang told the BBC. "They have their own people everywhere. Mitko was very close to one of them."
It is not clear when Mitko became aware that his cargo of refugees had died.
On the day he drove across Hungary into Austria, the temperature was baking-hot.
The first thing he may have noticed was the stench of decomposing bodies.
The lorry was found abandoned on 27 August in a lay-by on the A4 motorway near the town of Parndorf in the province of Burgenland, just 30km to the west of the Hungarian border.
That same day the Austrian capital was hosting a summit of European leaders called to discuss a dramatic spike in the migrant numbers heading through the Western Balkans. Among those in Vienna was German Chancellor Angela Merkel.
As they met, police in white forensic suits combed the lay-by near Parndorf for evidence.
A police spokesman said they initially thought the vehicle had been involved in an accident. But there was no sign of a driver.
They then noticed blood and other bodily fluids seeping out of the back of the lorry. When they opened it up they discovered dozens of bodies in an advanced state of decomposition.
How Parndorf changed the migrant crisis
The German chancellor said the leaders in Vienna were "all shaken by this terrible news" and she called on Europe to act together to solve the migrant crisis.
Austria's then-interior minister spoke of a dark day and called on Europe to fight people smuggling together.
"The best way is to build legal ways through Europe. With legal ways we can protect the refugees and the criminals have no chance for the business," said Johanna Mikl-Leitner.
The lorry, meanwhile, was taken to a shed in a lorry park at Nickelsdorf on the Austrian border with Hungary. Officials began the terrible task of extracting the bodies and identifying the victims.
It was only a few days later that Austria opened its border at the Nickelsdorf lorry park, to allow thousands of migrants who had become blocked in Hungary to continue their route towards Germany.
Unwittingly, the migrants walked past the lorry as they crossed into Austria. The forensic work was still going on.
The victims' story
Identifying the victims has proved difficult. One of the 71 is yet to be named. But some of their stories have emerged.
Five of the victims came from Iraqi Kurdistan, according to a Reuters investigative report.
Two of them, Semian Nasser Mohammed, 25, and Nashwan Mustafa Rasoul, 28, were cousins from a well-off family in Dohuk, some 50km south of the Turkish border.
Although their families had tried to dissuade them, the two men took the bus from Dohuk to Istanbul on 11 August.
Both had fought in the Kurdish Peshmerga army against jihadist group Islamic State. Both were disillusioned and frustrated by conditions in Iraq, according to Rasoul's older brother, Sarbast. They wanted to get to Europe, and start a proper life.
Mustafa sold his car to finance his trip.
In Istanbul, the story goes, they met Sediq Sevo, another Iraqi Kurd from Zakho, to whom they had each paid $7,500 (£5,600; €6,600) for the through-trip to Munich.
He arranged transport to the Turkish-Bulgarian border and they walked for at least seven hours across the mountains, before being met by Bulgarian smugglers on the far side, who took them to Sofia.
After several days in a Sofia apartment, they were driven to the Serbian border, trekked through more mountains and were registered by the Serbian police at Dimitrovgrad.
From there, a bus took them to Belgrade, and after several days in an apartment they were driven by car to Horgos on the Hungarian border.
At around midnight on 24 August they walked down the railway across the unguarded Hungarian border at Roszke, past the fence the Hungarian authorities were building, accompanied by an Iraqi Kurd called Bewar.
Bewar was supposed to take them to Germany himself, according to Reuters. Instead, he handed them over to an Afghan based in Budapest, who is now awaiting trial with Mitko.
Back in Iraq, when Sediq Sevo discovered that his clients had perished in the truck at Parndorf, he rang Bewar to complain. Eventually, one of Bewar's men explained the risks of such journeys.
"Explain that to the families [of the victims]…tell them not to complain about Bewar."
Facing trial in Hungary
Mitko is currently in pre-trial detention in Hungary, along with five other suspects, four of them from Bulgaria and one from Afghanistan.
The trial will begin in Kecskemet this autumn, once the police investigation is completed, according to Gabor Schmidt, spokesman for the prosecutor's office in Bacs-Kiskun county.
Mitko's family hopes that his defence lawyer can prove that he was only a small cog in a very long chain - reaching all the way from Afghanistan to Germany.
Hungarian police are confident that he and his accomplices will get close to the maximum 16-year sentence foreseen by laws deliberately tightened last year, to deter potential smugglers.
"This was not the first nor the last human shipment organised by this group," says Zoltan Boross, head of the anti-trafficking unit of the Hungarian police. "That vehicle required a very serious logistical background, with very serious money and a very serious circle of people."
Catching the smugglers
The Nickelsdorf lorry park is no longer full of refugees. Over the past year, first Hungary, then Austria and Western Balkan countries shut their borders to migrants and refugees travelling up from Turkey via Greece.
In April, a border management system, run by the police and supported by the army, was introduced to stop smugglers and illegal immigration.
These days, long queues on the motorway and on the side roads leading from Hungary to Austria are common, as police check cars, vans and lorries at the border for people smuggling migrants.
The police have a scanmobile, which can X-ray lorries for human cargo.
Opposite the shed where the lorry was kept, around 40 cars, used by smugglers, have been impounded by the police. Among them are number-plates from Romania, Poland, Italy and the UK.
Police in this part of Austria say they arrested 84 smugglers here in the first six months of this year.
It was their job to identify the victims in the lorry found at Parndorf, and forensic investigators succeeded with 70 of the 71.
"It was very important for the police to establish who these people were and to inform their relatives about the terrible deaths of their brothers, sisters fathers and sons," said Burgenland police spokesman Helmut Greiner.
Remembering the victims
Most were taken back to their families, including the bodies of Semian Nasser Mohammed and Nashwan Mustafa Rahoul, which were flown home in late September 2015 during the Muslim Eid al-Adha, the Feast of the Sacrifice, and are buried in a hillside cemetery in Dohuk.
But 15 of the bodies were laid to rest in Vienna: the unidentified victim and one other person in the city's Central Cemetery and the rest in the Muslim cemetery in Liesing.
Carla Amina Baghajati from the Muslim community in Vienna, attended one of the funerals. "It was one of the most emotional moments in my life. It is horrible to see the coffins go one by one into the ground."
She has seen a dramatic change in sentiment in Austria toward refugees, and towards Islam, since the lorry was discovered last year.
"While we saw a tremendous wave of help after this tragic accident, things changed. People felt that refugees had come into the country in too large numbers," she said. "It is a very difficult time."
If you drive past the lay-by at Parndorf on the road from Nickelsdorf to Vienna, you can still see a small memorial to the 71 who died.
Flowers and a candle in a glass lantern had been placed close to the site.
"There are always candles there," says Helmut Greiner. "Some people remember."