Architecture has lost a great visionary. Budapest-born French architect Yona Friedman died at age 96 on Feb. 20.

Friedman left us with a lot to remember. Some obituaries commemorated his pioneering work — some of it with UNESCO — on self-sufficiency, empowerment and do-it-yourself architecture. Others have restated the influence his emblematic “Spatial City” (Ville Spatiale) — a three-dimensional grid floating above urban and natural territories and populated by mobile dwellings — had on an entire generation of architectural experimentation.

Others yet have recognized his bold theories about social transformation and the necessity of fluid mobility in buildings and cities — or recalled his experiments using computers to help inhabitants plan the Spatial City when architects were only just beginning to explore using computers.

Perhaps Friedman’s most remarkable feat was the presentation of bold visions about the future of cities, human societies and how to allocate environmental resources, with a level of detail that made them appear like imminently realizable scenarios. His “realizable utopias” — as he called them — moved between a sober plan and a daring dream.

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