The first time Ahmed saw England was when he pulled back the tarpaulin of the lorry he had been smuggled onto, and jumped down onto the street in Luton.
Ahmed's story is typical of a growing number of young migrants
It was early 2009. He wasn't sure of the date and couldn't say exactly how long he had been on the road since leaving northern Afghanistan the year before.
All he knew was that it was still hot when he crossed into the Iranian desert during the first days of the journey, and freezing cold by the time he neared its end in northern Europe.
Along the way he had ducked under searchlights, taken part in a car chase, been stowed away on boats and picked up by the police, on a journey that migration experts say is typical for a growing number of Afghan children making their way, unaccompanied, to Europe.
They were experiences that might force a teenager from rural Afghanistan to grow up fast, but his first reaction on arrival was apparently childlike.
"It was very cold," he says, "there was snow everywhere. There were boys who were playing in the snow and one of them threw a snowball at me, so I joined in and for 10 or 15 minutes. I played."
Ahmed, who says he is now 16, made his journey alone.
He says he left Faryab province in northern Afghanistan after militants asked him to plant explosives on cars that local officials brought to the garage where he worked, and threatened to kill him when he refused.
Until then he had been untroubled by the violence plaguing many parts of his country, but the security situation was deteriorating and his family felt they had to leave.
Ahmed, whose name has been changed to protect his identity, says he was refused asylum but given leave to stay in the UK - a status commonly granted to unaccompanied minors, or under-18s.
His stated reasons for leaving have not been verified, but he gave the BBC an exhaustive account of his journey.
It was an uncle who arranged the trip, which migrants say can cost tens of thousands of dollars.
Ahmed said he was not initially told he was being sent to England - nor that he would be separated from his family. That moment came after a couple of days of driving when, as he later realised, he had just crossed into Iran.
"They were putting everyone in cars, they were in a hurry and talking in a foreign language I didn't understand," he says.
"I wanted to be with my family at that stage but two people forced me into one of the vehicles. I was crying, I didn't want to go. We didn't get to say goodbye."
Iran to Istanbul
Several days of continuous driving followed, initially in the open back of a truck.
"There were 25 people in the back of the pick-up, with some of them piled on top of each other or hanging from the rails," he says.
"The weather was so hot that some fainted. There was no cold water to drink and they didn't even stop when people needed to relieve themselves."
The group, which included Afghan men of various ages from different parts of the country, crossed into Turkey, but only after being ordered by smugglers to drop to the ground to avoid a swivelling searchlight at a border post.
The journey then proceeded at a less frenetic pace, with trips in cars and buses and a comfortable stay in Istanbul with an Afghan intermediary - who, like Ahmed, was from the Uzbek speaking part of the country.
It was there that Ahmed says he heard for the first time that he was headed for England, and was told that there were two options for travelling on to Greece - by sea or by land.
Afraid of the sea, which he had only seen for the first time in Istanbul, he chose land.
He might have regretted it. Approaching the border by car with two other migrant teenagers, the Afghan intermediary, who was driving, had to swerve off the road into fields to avoid a checkpoint where vehicles were being searched, and was chased for a while by a police car.
And there was still water to cross at the border. The group of four used a pair of inflatable dinghies, though the one Ahmed was in capsized when his companion tried to throw his rucksack onto the far bank.
Ahmed currently has temporary leave to stay in Britain
Drama gave way to boredom in Greece, with several months of waiting while the next leg of the journey was arranged. Time was wiled away playing computer games in a flat. Ahmed never learned the name of the city.
Then came one of the biggest tests, as he travelled to Italy by boat, stowed away in a tool compartment in the base of a car-transporting lorry for about 15 hours.
"There were two of us squeezed in tight," he says. "It was very cold - so cold that our backs felt like they were frozen. We were not even able to reach for our bags to get something to eat."
There were more cold temperatures to bear as he travelled north through Italy, where he spent several nights sleeping rough outside a large station - probably Milan.
Eventually sneaking onto a train to France, he was so exhausted that he slept, only waking as he was carried off by police in Paris and deposited on a station bench.
From the French capital, he managed to call the intermediary in Greece, who put him in touch with another Afghan in the smuggling network, this time in the northern port of Calais.
There he stayed in "the jungle", the notorious informal migrant camp that French authorities closed down in September.
At one point, after being stung during a police raid by what he suggested might have been tear gas, local authorities sent him to a French carer family.
But he escaped, determined not to be frustrated so close to his goal.
There were two failed attempts to get passage across the channel. Once, French police scanners detected him in the back of a container. Another time, he clung to the undercarriage of a lorry, but it drove for two hours in the wrong direction.
Both times, French officials simply sent him back to the Calais camp.
It may be that he has thick-padded boxing gloves to thank for crossing to England on his third attempt. He noticed them among the sports equipment that he and a group of others were told to burrow into to avoid detection.
Four were caught by scanners and dogs at the French border controls, and two more at the English ones.
"The lorry boarded the ship, which after a while arrived in port," Ahmed says. Once it was moving again I came out from my hiding place, thinking I was the only one left. But there were four others with me, still hiding under the goods."