On the museum wall, an impossibly rare Happy The Man Stereo/Mono acetate on a Bell Sound Studios label, the only official mono version that I know of. And the accompanying radio promotion reel about Genesis' December 13, 1972 Philharmonic performance, likely not heard in over 50 years.

Thanks to Chris Davies-Garner who expertly pieced together the failed splices and transferred the radio reel:
https://www.genesismuseum.com/WNEW1972.wav