From very early on, symposia and congress business were very important for the Cologne fairs. The Spring Fair in 1925, with which numerous congresses were already affiliated, was the first large trade fair. With growing success in the Fifties, Koelnmesse enlarged its congress facilities first with the Rhinesaal and then with the Auensaal. It became evident that the location of the Congress Centre in the direct vicinity of the actual fair grounds was a remarkable advantage. With the complete development of the fair grounds in 1977, the new Congress Centre East was also inaugurated. Since that time, Koelnmesse, as the fourth largest fairground in the world, has had two completely independent congress centres that can be used for every size of event, and since 1982 have been officially run as the Congress Centre East and West Koelnmesse. Koelnmesse now had congress centers which were independent of each other and could be used for all sizes of events, up to 2005 officially operating as Congress-Centrum Ost and West Koelnmesse.