RKU Sosnowiec - AKS Chorzów - 29/09/1947
Source: Wikipedia
After a match on 29 September 1947 in Sosnowiec, between RKU Sosnowiec and AKS Chorzów (ethnic rivalry, derby) fighting broke out resulting in the death of one fan and scores of others injured. Sosnowiec won the match 3-2, however in the first leg AKS Chorzów had won 3-0, meaning they were promoted to the First Division. After the match, 20,000 home fans were slowly moving out of the stadium, pushed by firemen and Milicja Obywatelska. Skirmishes broke out, and the Milicja Obywatelska functionaries, with guns, lined up on the pitch and attacked the fans with bayonets and the fighting lasted for two hours. Sosnowiec fans tried to attack AKS's players, the referees and the Milicjants.