The Museum of Mining is located just 5 km from the Kralovec–Lubawka (PL) border crossing. Black coal mining in the Zacler region has been documented by written historical records since 1570. Intense industrial extraction of black coal began in the 1930s by opening the perpendicular shafts Jiri, Frantiska, Marie, Julie and Eliska. For economic reasons, the mining gradually waned. In the 1950s the Jan shaft was excavated. Deep extraction in the Jan Sverma Mine ceased at the end of 1992. Some 75 mil. tons of black coal remains underground. It is the only mine in the Czech Republic completely filled with underground matter. The working area has been preserved. The Zacler Mining Museum is located in the engine rooms and pit-head buildings with the shaft towers of Jan and Julie shafts. The engine room in the Jan pit offers an exhibition documenting the history of mining in the Jan Sverma Mine and in the Zacler quarries.