A child hoists a rock at a gold mine in Montgbawalu, Democratic Republic of Congo (DRC). The troubled and war-torn northeastern region of the country has some of the world's biggest gold deposits.

But for years competition to reap its riches - with the labor of men and boys who spend all day digging without any help from modern machinery - has helped fuel armed conflict, including a 1998-2003 war that resulted in up to four million deaths.

See related essay: Digging for 'tainted gold' in Congo