Pierre Auger Observatory is a project with scientific collaborators from all over the world. The initial construction costs were shared by 15 different countries. Ongoing work and upgrades are paid by a variety of international funding sources. To get some sense of that, see [1] and the Acknowledgements section of journal papers arising from work there, such as [2].

[1] https://www.auger.org/collaboration/funding-agencies

[2] https://iopscience.iop.org/article/10.3847/1538-4357/acc862