Magufuli ordered military to build Great Mirerani Wall to control illegal mining.
Tanzania's President John Magufuli has officially inaugurated the Great Mirerani Wall, built in the north of the country to prevent the theft of tanzanite, a rare gemstone.
In September, Mr Magufuli ordered the military to build the wall, which is 24km long, in order “to control illegal mining and trading activities”.
The blue-violet tanzanite gemstone is found only in the country.
This is the first time Tanzania has built a wall to protect its mines, and some believe that other countries grappling with smuggling may also build them.