History of Cologne was considered a substitute for the German University of Strasbourg, which became part of France along with the rest of Alsace. Cologne prospered during the Weimar Republic and progress was made especially in governance, city planning and social affairs. Social housing projects were considered exemplary and were copied by other German cities. As Cologne competed to host the Olympics, a modern sports stadium was erected at Müngersdorf. Beginning of the 1920s civil aviation was permitted once more, and Cologne Butzweilerhof Airport soon became a hub for national and international air traffic, second in Germany only to Berlin Tempelhof Airport. At
Historical Archive of the City of Cologne municipal archive and library was erected between 1894 and 1897 to a Gothic revival design by Friedrich Carl Heimann: it was inaugurated in December 1897. The new building was large enough to accommodate the archive at a time of accelerated growth when the city of Cologne was absorbing many previously independent towns and villages. During World War II the building suffered damage from bombing. However, since all records and manuscripts had been moved into secure storage from as early as September 1939, the archive did not suffer any substantial loss. Since the archive moved to its new location in 1971,