In Botswana, they call Jwaneng “the prince of mines”. At 1.5 miles long and 400m deep, it is the largest and most valuable diamond mine in the world. Its stepped sides climb down into the earth, where excavators carve out the valuable kimberlite that is processed into rough diamonds – around 6kg a day.

Patience Gwaba drives a giant truck at the mine, hauling 300 tons of earth, 10 times a day. She is one of nearly 7,000 workers at the mine, a direct beneficiary of the diamond wealth that has transformed her country.

“There were no jobs, so I applied for this one,” she says.

In September Botswana celebrated 50 years of independence from Britain. The country has gone from being one of the poorest in Africa to one of the wealthiest and most stable, thanks to the discovery of diamonds and its long-standing partnership with mining house De Beers.