How do you survive in the coldest place on Earth?
In Siberia, the winter temperature can drop to -60C, making it one of the coldest places to live in the world. In the first of our series on extremes, Adam Mynott finds out how the people of Oymyakon district cope with everyday life under such extraordinary conditions.
It was extremely cold.
Stepping off the plane from Moscow into the brutal, brittle cold of Yakutsk in eastern Siberia, I could hardly believe that humans could survive, let alone thrive in such harsh conditions.
Yet this was a relatively mild start to my 10 days in the region. The temperature was -32C, and I was to encounter much worse.
One of the first things I noticed in Yakutsk, the regional capital of Sakha province, was that this city must be at severe risk of flooding, as all the buildings were built on concrete and steel stilts, suspending them 2m (6ft) above the ground.
But Valentin Spector, a senior researcher at the Permafrost Institute, said the stilts had nothing to do with flooding.
He explained that in the summer, when temperatures can rise to more than 40C, the top layer of frozen ground warms and defrosts, in some places to a depth of a metre and in others to as much as three metres.
This "active layer," as Mr Spector called it, is very unstable, and unless the foundations of buildings are firmly rooted deep in the permafrost below, movement in the summer will bring them crashing down.
He told me that 65% of Russia sits on permafrost, and in some places in Siberia the frozen ground is 1500m deep.
The permafrost poses many other difficulties. Even though the summers are hot, it takes a long time for the topsoil to shake off the chill, and the growing season for farmers is shoe-horned into a small period of a few weeks.
The following day we flew to Ust-Nera, a town north of Yakutsk, inside the Arctic Circle and deep in the mountains.
The air temperature fell another 10 degrees to around -42C, another startling shock to my life-support system.
As we drove into the town from the airport, we fell in behind a column of cars on their way to a funeral. Another problem posed by permafrost: how do people bury their dead in the middle of winter?
It takes two or three days to dig a grave in frozen ground.
A fire is lit and coals are piled on; after a couple of hours the coals are dragged to one side and the 15cm of ground defrosted by the heat and flames are dug and cleared. Hot coals are then pushed into the hole and the process begins all over again until the hole is 2m deep.
I was beginning to get used to the cold, but I still found it shockingly painful and difficult to operate in.
In the winter here, no-one goes outside unless they absolutely have to, and if they do have to venture out to shop or go to school or work, they are very well wrapped up.
Fur hats and long fur coats are everywhere.
A long fur coat can cost more than $1550 (£1000), beyond the purse of many people where the average wage is the equivalent of $600 (£400) a month. You can take out a mortgage on a fur coat - banks will lend to enable people to buy the garment they need.
I arrived with more sets of thermal underwear than I knew what to do with, but what I lacked was a good hat.
I was told by everyone that real fur was the only sensible solution, but I did not want to be responsible for the death of an Arctic Fox or a rabbit and, frankly, the real fur hats were very expensive, so I decided to go for fake fur.
This caused snorts of derision from the government guide who was accompanying me. He looked at me with a mixture of pity and contempt.
"Huh, Greenpeace," he said.
The town of Ust-Nera started as a small settlement after geologists discovered gold and other minerals in the region in 1937.
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Soviet leader Joseph Stalin saw the underground reserves as one solution to deal with bourgeois "enemies of the state," and sent many tens of thousands of political prisoners to gulags (work camps) in Siberia to extract the gold and other minerals with picks and shovels.
Mikhail Ivanov is one of the few gulag workers who survived the ordeal and is still alive.
I met the academic and historian in his apartment in Yakutsk, where he told me his crime had been just to praise the writings of a Yakut accused of being a nationalist.
After a sham trial, he was sent to work in a coal mine.
"If I dragged 25 wheelbarrows full of coal up to the surface, I received two bowls of porridge. If I couldn't manage 25, I got just one bowl," he told me.
The mines are still operating under, of course, totally different regimes. The money they offer in wages attracts miners from all over Russia and beyond.
It is the mines that sustain the economy in this barren cold environment. And without the mines, the town of Oymyakon, which is the coldest inhabited place on Earth, would probably only be occupied in the summer by reindeer herdsmen.
When I visited the Badran gold mine, the temperature above ground was -45C. I found it almost unbearable.
Andrei Dubov, who has worked at the mine for a decade, said the cold was no problem.
"I wrap up warm, and it's dry. So it's a much better climate than many other parts of Russia." He said the coldest temperature he could recall was -63C.
"It was probably colder," he told me, "but the thermometer only reads down as far as -63C."
-52C and falling
Underground, the miners work in temperatures between -15C and -20C, which seems appalling, but remarkably, the mine feels incredibly mild, warm even.
The coldest temperature I experienced in my few days in Siberia was -53C.
This was so cold that after no more than a few minutes outside, exposed skin started to smart with pain, damp surfaces in my nostrils froze, and toes and fingers turned uncomfortably cold very quickly, despite three layers of thick socks and two pairs of gloves.
I was carrying my microphone, and the flexible cable that led to the recording machine turned as rigid as a stick and I was warned that if I tried to bend it before it warmed up, it would snap.
It is easy, perhaps even arrogant, to look at the lives of the people who live in the district of Oymyakon and think they would not live in such a physically demanding place if they knew better. Of course, they do know better.
I visited the Vadreyev family, who were all born in Ust-Nera and feel they belong to the town and its people.
As she dressed her daughter, Maria, in a thick fur coat, fur hat, scarf and gloves, Martina Vadreyev said: "Sure, we have to wrap up warm. In other parts of Russia you can throw on a coat to go outdoors, here it takes ages to dress. But we are used to it. This is our home."
Then the two of them pulled open the door of their apartment and stepped into the blast of super-chilled air -52C and falling.