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
Cologne European trade fair location with over 50 trade fairs and other large cultural and sports events. In 2008 Cologne had 4.31 million overnight stays booked and 2.38 million arrivals. Cologne's largest daily newspaper is the "Kölner Stadt-Anzeiger". Cologne shows a significant increase in startup companies, especially when considering digital business. Road building had been a major issue in the 1920s under the leadership of mayor Konrad Adenauer. The first German limited-access road was constructed after 1929 between Cologne and Bonn. Today, this is the Bundesautobahn 555. In 1965, Cologne became the first German city to be fully encircled by a