Historical Archive of the City of Cologne up at the site of the collapse (a large hole in the ground), where around 95% of all archival items could be held until August 2011, albeit scattered and in many cases badly damaged. Archive repositories all over Germany offered space to store the damaged and only roughly cleaned documents: wet materials were flash-frozen to prevent mold growth. "Itinerant archivists" worked in the receiving archives all over the country and began the task of re-identifying and re-cataloging. A newly installed centre for restoration and digitization on the outskirts of Cologne started working in 2011, with a total cost for restoring
Demographics of Cologne over the old city walls in 1794, just short before the arrival of French troops and Cologne's incorporation into the First French Empire. After 1815, the Kingdom of Prussia enforced the construction of fortifications which again hindered any growth for the city. Only with the acquisition of these fortifications in 1881, the city of Cologne had the possibility of a gradual territorial expansion. On 12. November 1883 a strip of territory from parts of the municipalities of Ehrenfeld, Kriel, Longerich, Müngersdorf and Rondorf was added to the city. Since 1886, the Cologne City Council intensified negotiations with the surrounding communities,