A robust, safe and spatially interesting connection that was thought impossible on this location. 50 meters wide drums on either side of the water enable cyclists to spiral up and down. In the open air, with views of city and sky. There are lifts, stairs and escalators for pedestrians. Once at depth, a slightly sloping tunnel with separate domains for cyclists and pedestrians crosses under the river IJ. The entire length of the tunnel is enriched with real plants that grow in artificial light. The IJ Klopper is much cheaper than a bridge, is always available (because it is never open), delivers a crucial contribution to sustainable urban transport as well as an original public space. Good for the image of Amsterdam city of cyclists.