Evidence

Roman harbor concrete has endured constant seawater for two thousand years while modern reinforced structures fail within decades — and three distinct threads of research, from ancient mineralogy to living bacteria to algae-grown limestone, are separately asking whether concrete could repair and renew itself instead of just wearing out.

A 70-story Miami tower with 500 photovoltaic-integrated windows, Michigan State's nearly invisible solar coatings, and the unresolved math behind the industry's most quoted "solar skyscraper" — what transparent solar glazing can actually generate today, and where the numbers don't add up.

A four-meter tower built from thread and loose gravel, MIT's shape-shifting 4D-printed materials, and the decades-old dream of self-assembling robotic "catoms" — what programmable matter has actually achieved for architecture, and what's still speculation.

How a mushroom-grown tower at MoMA PS1 and a Cardiff University insulation study test whether architecture can be cultivated, not manufactured — and where the material still falls short.

PLACEHOLDER standfirst — replace before publishing.