The price of the rare earth metals the world buys from China
When you stand on the edge of Bayan Obo, all you see is an expanse of scarred grey earth carved into the grasslands of Inner Mongolia in northern China.
Dark dust clouds rise from deep craters where the earth’s crust has been sliced away over decades in a search of modern treasure.
You may not have heard of this town – but life as we know it could grind to a halt without Bayan Obo.
The town gets its name from the district it sits in, which is home to half of the world’s supply of a group of metals known as rare earths. They are key components in nearly everything that we switch on: smartphones, bluetooth speakers, computers, TV screens, even electric vehicles.
And one country, above all others, has leapt ahead in mining them and refining them: China.
This dominance gives Beijing huge leverage – both economically, and politically, such as when it negotiates with US President Donald Trump over tariffs. But China has paid a steep price for it.
To find out more, we travelled to the country’s two main rare earth mining hubs – Bayan Obo in the north and Ganzhou in the province of Jiangxi in the south.
We found man-made lakes full of radioactive sludge and heard claims of polluted water and contaminated soil, which, in the past, have been linked to clusters of cancer and birth defects. These journeys were challenging.
Beijing appears sensitive to criticism of its environmental record. We were pulled over by police, questioned by them and stuck in a three-hour standoff with an unidentified mining boss who refused to let us leave unless we deleted our footage.
Our calls for an interview or a statement have gone unanswered, but the government has published new regulations to try to strengthen its supervision of the industry.
Authorities have been making an effort to clean up these mining sites, scientists told the BBC. Still, China’s mining operations in the north just keep growing.
Machines are constantly on the hunt for rare earths called neodymium and dysprosium that go into making powerful magnets for a variety of modern technology, from electric vehicles to computer hard drives.
To find these rare earths, the machines strip away the topsoil layer-by-layer, kicking up harmful dust, some of which contains high levels of heavy metals and radioactive material.
Satellite images from the last few decades show how the Bayan Obo mine has spread.
The mine sits in the vast, aridness of Inner Mongolia, a nine-hour drive from the capital, Beijing.