History of Cologne (Cologne Tower), one of Cologne's most prominent highrises. Secondly, a permanent improvement in traffic infrastructure, which makes Cologne one of the most easily accessible metropolitan areas in Central Europe. Due to the economic success of the Cologne Trade Fair, the city arranged a large extension to the fair site in 2005. The original buildings, which date back to the 1920s, are rented out to RTL, Germany's largest private broadcaster, as their new corporate headquarters. A controversy started after Muslims in Cologne sought to build a mosque. Most important for the history of Cologne since the Middle Ages is the Cologne
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