With sections of sand, solid rock and even worn-down bridges that drivers must inspect before crossing, the 200km road takes nearly 24 hours to drive.

BBC: Seven of the world��s riskiest roads

And sometimes we find that vast mountains of it have been worn down by erosion and that the cassiterite is now spread through the silt and sand of an ancient estuary.

FORBES: After Conflict Minerals Comes The Death Metal: Tin. And It's Apple's Fault Again.