From what I read (Close To The Edge book), the show was cancelled because no one attended and some roadie turned all equipment in a wrong voltage and it all burned down. I don't remember the details and I don't have the book with me, but it was something like this. After this, the three bands (Yes, Nice and Bonzo Dog) were of course, sad. Then, Keith Emerson began hammering the piano and singing a bizarre version of Give Peace a Chance (sung as Give Booze A Chance). All the three bands sang together, and boozed together. That same night, they returned to England by plane and the pilot announced that the Armstrong had stepped on the moon. Cool.