With SEMBLA®, we introduce the first solid masonry system designed for circularity and reuse. SEMBLA® is distinguished by its easy (re)assembly without mortar or glue and its use of cement-free geopolymer concrete, cutting CO2 emissions by up to 70%. The system's hollow block engineering and micro modularity offers design flexibility while delivering ecological and economic advantages. Guided by the Cradle-to-Cradle principle, we consider buildings within their entire lifecycle.