This project envisions a new science and technology that turns low-tech concrete and cement-based materials into high-tech functional photonic metamaterials. In particular, the MIRACLE project will construct and test a revolutionary Photonic Meta-Concrete (PMC) whose response to light will be engineered for exhibiting radiative cooling ability; i.e. the PMC will be able to expel heat from buildings to the outer space without any extra energy consumption. Though this ambitious challenge can have a big impact in the Nearly-Zero-Energy-Buildings (NZEB) uptake, the concept of PMC transcends this particular application, with multiple implications in avenues like solar cell-technology or communication technologies, for example. Radiative cooling technology utilizes the atmospheric transparency window to passively dissipate heat from the Earth to outer space. This technology has attracted wide interest from both fundamental and applied sciences, due to its a priori potential in multiple applications like building cooling, renewable energy harvesting, or even dew water production. However, currently the development of this technology is in a bottleneck, where the scientific ideas have negligible potential impact in any real-world energy solution. In this context, the MIRACLE consortium proposes a considerable advance in the state-of-the-art because it will address for the first time an effective and fully scalable solution based on steel microfibre reinforced concrete ! The idea of MIRACLE is to propose new designs where an ordered arrangement of the steel microfibres can work in combination with hierarchical porous structure of concrete as a PMC. For this challenging objective, advanced optimization methods based on deep learning technologies will be employed at the design level, while the fabrication will rely on an inverse-phase methodology where micro-patterned concrete mould will be produced by two-photon-polymerization (2PP).