Drones called in to save the Great Wall of China

A very 21st Century piece of tech is being called in to save the crumbling Great Wall of China. from BBC News - World https://ift.tt/2QfWj...

A very 21st Century piece of tech is being called in to save the crumbling Great Wall of China.

from BBC News - World https://ift.tt/2QfWjbS