self–pollution:An underground town by the name Coober Pedy is a small mining town with a population
self–pollution:An underground town by the name Coober Pedy is a small mining town with a population of just under 2,000, but it’s also the “opal capital of the world” and has been supplying most of the world’s gem-quality opal since it was founded in 1915. In this waterless environment, not much activity goes on above ground and instead, the community exists in a network of tunnels underneath the desert earth, inside some 1,500 homes and dwellings they call their “dug-outs.” (Via) -- source link