In begin of 1960s made the Italian sculptor Marino Di Teana A outrageous proposal for Urban future of France
He simply proposed to demolish every city, town and village in France! and replace them by 400 Urban centres with each 20000 inhabitants, each 20 km apart along transport axes in France.
Connected are those Urban centres with highways high speed trains, oddly i found no info about airports or helicopter pads for those Centres.
Each centre have average of three hundred meters in height and eight hundred meters in width. designed with housing as well as areas for economic activity and public buildings. with underground areas for communication and services, including nuclear fallout shelters in case of War !
Marino Di Teana and model of a Urban Center in 1964.