Demographics of Cologne and on 1 April 1888 ended in a first major incorporation. The territorial expansion, beginning in the late 19th century, were significant marks for the city's population growth. Major communal reorganizations took place in 1910, 1914, 1922 and 1975. Demographics of Cologne Cologne () is Germany's fourth-largest city and the largest city in the Rhineland. As of 31 December 2011, there were officially 1,017,155 residents. The city is center of the Cologne/Bonn Region with around 3 million inhabitants (including the neighboring cities of Bonn, Hürth, Leverkusen, and Bergisch Gladbach). The walls of Colonia Agrippina covered an area of 96.8 hectares,
Transport in Cologne German limited access highway ("autobahn") was opened in 1932 between Cologne and Bonn. Today, this is A 555. In 1965 Cologne became the first German city to be fully encircled by a beltway. Shortly after the Second World War reconstruction plans by, among others, Rudolf Schwarz called for a downtown bypass freeway (the ) as a centerpiece of rebuilding the city. These schemes were only partially executed though, due to opposition by environmental groups. The completed section became "Bundesstraße (Federal Road) B 55a" which begins at the "Zoobrücke (Zoo Bridge)" and meets with A 4 and A 3 autobahns at