The Ústecký Region is one of the most industrialized areas in Central Europe. The economy used to be based on metallurgy and the chemical industry, though is now more diverse. The region's traditional branches of industry are chemicals and petrochemicals, engineering and thermal energy. Historically, the economic importance of the Ústí nad Labem Region lay in its reserves of raw materials, especially deposits of brown coal, quality glass and foundry sands and building stone. The brown coal basin stretches under the hillsides of the Ore Mountains from Ústí nad Labem to Kadaň.