This research contributes to planning theory and praxis and is an international comparative approach. The global stock of early and mid-century modernist/Bauhaus and Bauhaus influenced low rise apartment developments are ageing, with many facing blight. The next step in their cultural heritage history urgently requires considered decision making. These buildings offer remarkable architecture, history and sustainability techniques. Some cities have been awarded UNESCO recognition for their stock eg. Tel Aviv – ‘the white city’. However, in the era of climate crisis, and emphasis on resilience via the circular economy, and urban regenerative futures, we query how this collection of buildings should be repaired, renewed, and revived for adaptive reuse, rather than demolished. Global cities are also situated within housing shortages, and we posit that these buildings can be adapted for greater housing density. The presentation will explore density increase and consider social, economic, heritage and sustainability impacts on residents and their communities. We raise bespoke issues for adaptive reuse in comparable countries, considering regulatory constraints (including heritage hinderances from being afforded UNESCO status). Of particular interest to the research are the specific needs that adaptive reuse must afford these buildings in certain countries eg.Türkiye, Greece, Australia, Israel, to provide underground parking, earthquake support, mixed use public facilities, and in some countries, even bomb shelters. Drawing on global literature, existing case studies, and comparative land use planning law, governance and policy, the research offers unique insights into what can and ought to be done for modernist buildings, rather than demolition for such a significant and rich array of buildings, now moving into their hundred-year anniversary.