ESO is actively preparing for the future ground-based facility after the ELT through the Expanding Horizons call. They are looking for the next transformational facility that will lead to groundbreaking scientific results. With this in mind, they opened a call for white papers to understand the community’s need for this future facility. Astronomical research infrastructure accounts for the biggest share of an astronomer’s carbon footprint (Knödlseder et al. 2022). We, a group of fellow A4E members, believe that the next ESO facility must be built and operated as sustainably as possible, ensuring that scientific discoveries and knowledge creation still go hand in hand with a livable future for all. In the scope of this white paper call, we submitted a contribution titled “A vision for ground-based astronomy beyond the 2030s – How to build ESO’s next big telescope sustainably”. We discuss the necessity for the next facility to take sustainability into account and we offer action items to incorporate sustainable considerations throughout the project. Our work is publicly available on ArXiv. Meaningful changes can happen if we act altogether, as a community, and we hope that astronomy in the 2040s will be up to the biggest challenge of Humankind: the climate and social crisis.