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 currently uses as home ground the Municipal Stadium Nikaia. Ionikos of Nikaia had a longstanding presence in Super League Greece and its home ground is the Municipal Stadium Neapoli. In basketball, Olympiacos B.C. is the only major club from Piraeus, one of the most successful at domestic and European level, and its home arena is the Peace and Friendship Stadium, while the volleyball department of the same club, Olympiacos S.C., is the dominant domestically and has made great success in European competitions as well. Piraeus rides really high in water polo, where Ethnikos Piraeus and Olympiacos departments have entirely dominated