Silesian Interurbans, one of the largest tram (streetcar) systems in the world, has been in existence since 1894. The system is spread over more than 50 kilometres (east-west axis) and covers thirteen towns in the Upper Silesia metropolitan area (Southern Poland) and their suburbs (Katowice, the capital town of the region, Będzin, Bytom, Chorzów, Czeladź, Dąbrowa Górnicza, Gliwice, Mysłowice, Ruda Śląska, Siemianowice Śląskie, Sosnowiec, Świętochłowice, and Zabrze), which is densely industrialised (coal, coke, steel and other industries; though decreasing since 1990s) and inhabited by more than 2 million people.
Read more about Silesian Interurbans: Basic Information, History, Present Day, Routes, Rolling Stock