PLATEAU is a digital twin initiative led by Japan's Ministry of Land, Infrastructure, Transport and Tourism (MLIT) that collaborates with various stakeholders to develop, utilize, and open “3D city models” across the country. Launched in fiscal 2020, this digital twin data of cities was created for around 200 cities across Japan by fiscal 2023 and continues to expand coverage. We have developed over 100 use cases in various areas, such as urban planning, disaster prevention, and environmental management. PLATEAU has been working to develop an ecosystem to promote open innovation in urban areas. The datasets are openly available in various formats. In addition, we release a wide range of knowledge, including guides, technical material, and source code for our website.