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 plan was also drawn up and approved by King Otto, but not completely fulfilled, as it was revolutionary for its time. The municipality was established in 1835, reviving the ancient name 'Piraeus'. Following petitions from the new and emerging prosperous bourgeoisie, municipal elections were held to elect a mayor for the city, Kyriakos Serfiotis of Hydra. Piraeus had around 300 inhabitants at this time. Piraeus, from a deserted small town, quickly became the leading port and the second largest city in Greece, with its prime geographical location and closeness to the Greek capital helping it continually to grow, attracting people