Back in the Netherlands he works with the architects Aldo van Eyck and Gerrit Rietveld. He likewise fosters and maintains his many international contacts, which also include those with the Danish artist Asger Jorn. Constant becomes ever more convinced that a new social and cultural order will advance the cause of humanity. His visionary spirit anticipates that the automation of production will provide mankind with increasing amounts of free time (thereby creating scope for the “Homo Ludens”, the man who is playful and creative) and that this futuristic view would become feasible in what, from 1960, is to be known as New Babylon.
This vision is what will dominate his oeuvre from that moment on. He makes drawings, models, photo collages, plans, constructions and paintings. In addition, he substantiates New Babylon with numerous written works, talks and lectures in various countries.
The social and political turbulence of the sixties threatens to turn New Babylon into a utopia: The New Babylon project stops in 1974.