ALMA2040 represents a community-driven effort to develop the requirements for a next-generation
transformational (sub-)millimetre telescope that will address the top scientific questions in
astronomy in the 2040s and beyond. The initial effort in Europe is focused on preparing a proposal
for ESO’s Expanding Horizons call, which represents its search for the next big astronomical groundbased programme. Following a successful meeting at the Haus der Astronomie in Heidelberg in May 2025, where initial suggestions for key primary (capability-defining) science drivers were presented and discussed, the goal of this Lorentz Workshop is to consolidate and sharpen the community feedback while simultaneously ensuring a shared technological vision. A key outcome of the workshop will be a coordinated series of White Papers highlighting the exciting and diverse range of science cases that would be made possible by such a facility.