France's Nord-Pas de Calais Mining Basin—along with its mining pit, workers' quarters and yes, slag heap—now joins The Great Wall and the Great Barrier Reef on UNESCO's World Heritage list.
The coal mine in northern France was active from the 1700s to 1900s. UNESCO weighs in on what the mining region contributed to world heritage.
"The site bears testimony to the quest to create model workers’ cities from the middle of the 19th century to the 1960s and further illustrates a significant period in the history of industrial Europe" writes UNESCO describing the site.
"It documents the living conditions of workers and the solidarity to which it gave rise."