Petrila is a very old settlement, yet it only started to grow exponentially after the communist regime of Nicolae Ceaucescu decided to industrialize the coal mining in this area.
Between 1948 and 1956 the population doubled from 10.000 to almost 20.000 and in 1992 Petrilla reached almost 30.000 inhabitants. Since then, the city is shrinking because most mines have closed.
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