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,
Historical Archive of the City of Cologne so-called White Book ("Weißes Buch"), a book of copies of charters and privileges. By 1370 the archives were located in the "Haus zur Stessen". In medieval Cologne, valuable goods and important trade documents were frequently stored in vaulted warehouses specially built in backyards. This method of storage was used by both business owners and the municipal administration. Documents included grants of privileges, contracts, records of lawsuits, maps, seals and documents from the estates of important persons. As the city and its national and international trade thrived and prospered, the municipal administration began to plan further storage to house the growing