Copenhagen Metro’s new ring is constructed within Copenhagen’s primary aquifer. A holistic and reliable groundwater management is therefore inevitable. On 29. September 2017 EKJ invited the Young Water Professionals Denmark to visit one of the construction sites. We learned a lot about groundwater management, the handling of contaminations, the relevance of the groundwater table for the foundations of old buildings in Copenhagen and much more. Many thanks to all organizers for the exciting tour!