The International Associated Research Centers for the Urban Underground Space (ACUUS) is an international non-governmental organization dedicated to fostering collaboration among experts in the fields of urban underground space research, planning, development, utilization, and management. Its core mission is to provide a platform for urban underground space, bringing together experts from multidisciplinary fields to promote consensus among global practitioners on initiatives for underground space development and infrastructure utilization, ultimately benefiting urban life.

As a pioneering force in advancing the global underground space sector, ACUUS influences both academia and industry. Its membership encompasses over 20 renowned institutions worldwide, including the French Association of Tunnels and Underground Spaces (AFTES), Beijing Jiaotong University(China), China Research Center for Tunnel and Underground Space Engineering, Colorado School of Mines(USA), U.S. Center for Underground Construction and Tunnel Engineering, and the Swiss Federal Institute of Technology in Lausanne (EPFL). With a history spanning 40 years, ACUUS has held 19 biennial conferences in various cities around the world, evolving into one of the most prominent academic conferences in the field of urban underground space globally.

Over the years, ACUUS has maintained a close collaborative relationship with the United Nations Human Settlements Programme (UN-Habitat). In October 2019, at the Global Urban Forum and World Cities Day in Shanghai, UN-Habitat and ACUUS jointly signed the *Memorandum of Strategic Cooperation on Enhancing the Contribution of Urban Underground Space Utilization to Urban Sustainable Development*. This memorandum aims to enhance the contribution of urban underground space to urban sustainability and resilience, providing appropriate and sustainable flexible solutions for local government decision-makers and UN-Habitat staff in areas such as urban drainage management and urban planning.