The Metropolis GZM is a metropolitan unit composed of 41 contiguous municipalities in the Silesian Voivodeship of Poland. The seat of the metropolitan council is Katowice, the largest city of the region and the voivodeship capital. With a population of over 2 million, the core of the Metropolis GZM is one of the largest urban areas in the European Union. The area of the metropolis largely coincides with the metropolitan area of the Katowice urban area, which is a part of the wider polycentric transnational Upper Silesian-Moravian metropolitan area, the latter with a population of 5–5.3 million people.

Bytom is a city in Upper Silesia, in southern Poland. Located in the Silesian Voivodeship of Poland, the city is 7 km northwest of Katowice, the regional capital.