The archaeological excavations associated with the construction of the north-south metro line in Cologne between 2004 and 2011 were the biggest engineering operation in the history of the city. Thanks to the largely sub-surface construction methods used in the excavation of the tunnel, earth-moving operations were restricted to the sites of the stations and supply and access shafts for the four kilometers of track. Between the future stations the original sediment was moved a long way beneath the levels affected by human occupation. The volume of earth examined amounts to 150,000 cubic meters. The archaeological investigations represent a unique cross-section through the more than two-thousand-year history of Cologne.
In addition to the "common" exhibition catalogue the following introductory booklet for young readers was published to accompany the exhibition.