The Fermilab herd was always one of the highlights of visiting there. I always thought that was a really good use for the space inside the accelerator, a nice version of nature and science coexisting. I have it in my head that we used to be able to just drive through Fermi to see the Bison (late 80s/90s).

More on the bison at Fermi: https://www.fnal.gov/pub/about/bisoncam/