The building sector is entering a new era of circularity and Le Colaz is leading the way! Funded by the European Commission under Horizon Europe, Le Colaz (“Building an Adaptable Future Brick by Brick”) is reimagining how we design, renovate, and reuse buildings. Inspired by LEGO-like modularity, Le Colaz develops a comprehensive framework that merges bio-based and recycled materials, snap-fit construction components, and AI-powered digital platforms to enable sustainable, adaptable, flexible, modular and circular building practices. Through its twin digital engines, the Internet of Materials (IoM²) and the Internet of Building Brain (IoB²), the project harnesses IoT sensors and Large Language Models to optimize reuse, predictive maintenance, and regulatory compliance. Validated through Living Labs in Athens and Trondheim, Le Colaz will demonstrate measurable gains in energy efficiency, circularity, and resource optimization. The kick-off meeting took place online on September 29, marking the beginning of a 42-month journey driven by a dynamic consortium of 12 European partners dedicated to shaping a smarter, greener, and more adaptable built environment.