Piraeus of social problems also emerged with the concentration of new populations in the suburbs of the old city, such as Nikaia, Keratsini, Drapetsona and Korydallos. The involvement of Greece in World War II came as a major setback to the city's progress. After the war, the city began its development once more, as damage to the port and the city were repaired and new additions took shape after 1955. Piraeus is now the third largest municipality in Greece; the city proper with its suburbs form the Piraeus urban area, which is incorporated in the Athens urban area, thus making Piraeus
Piraeus derby the 1985–86 season and has not finished above Olympiakos in the league standings since the 1987–88 season. In the 1990s, when Olympiacos was experiencing probably the greatest era of its history while Ethnikos was suffering through what was surely its worst, Ethnikos lost some of its fanbase to Olympiakos. A recent point of contention for Ethnikos fans has to do with Karaiskakis Stadium. Karaiskakis is the traditional home of both Olympiakos and Ethnikos, but only Olympiacos has played there since the stadium was rebuilt for use in the 2004 Summer Olympics. Piraeus derby The Piraeus derby, is an association football