Inside Kazakhstan's giant crypto-mine
Last year Kazakhstan became the second biggest crypto-currency mining country in the world, thanks partly to a vast mine containing 50,000 computers in the desert near the northern city of Ekibastuz.
Young men work 12 hours a day for 15 days in a row without leaving the site, in order to keep it running round the clock.
But the rapid growth of crypto-mining in the country has put pressure on the energy sector, which relies heavily on polluting, carbon-intensive coal-fired power stations.
Earlier this month the rising cost of car fuel acted as the trigger for nationwide political protests. For five days the Kazakh crypto-mines could not connect to the internet, causing crypto-currency transactions across the world to slow down.
You can watch the full documentary, Our World - Kazakhstan's Crypto-Boom? on BBC News and BBC World News, from Friday 4 February and during the weekend.
Reporter: Joe Tidy
Producer: Natalia Zuo