The Melbourne Cricket Ground following the conclusion of the Closing Ceremony at the 1956 Olympics.
The image was taken from the Member's Stand, and from what I recall, Bay 13 was around the centre of what is shown of the portion of the stand to the left.
I may be wrong - I was once, I think it was on a Tuesday afternoon, but I could be wrong - but I don't think the old Bay 13 and the current one are the same location (although it's difficult to tell with the massive change in the grandstands of yesteryear and today).
A couple of sites I checked put Bay 13 today immediately opposite the Member's Stand, but I seem to recall in our day, it was fairly close to the latter. I think the Southern Stand extended to about Bay 16, there was the old scoreboard and then the Member's - on an arc, it would have been perhaps 30 to 40 degrees rather than the 180 degrees implied by "directly opposite".
Oddly enough, I couldn't find a definitive picture of Bay 13, but I do know where the original enamel sign is!
It was souvenired by the brother of an acquaintance at the Preston Football Club Social Club.
He (the acquaintance) was a security guard at the G when the stand was bulldozed and his brother worked as part of the demolition team.
The latter saw the sign screwed into a lump of concrete about to be loaded onto a truck and decided that at that stage, obviously nobody wanted it and with a few quick twists of a screwdriver, "Bay 13" was liberated. The security guard was conveniently distracted at the time.
It now lives happily in a garage in West Preston and is believed to be writing a book of memoirs which may or may not include the Control Data Australia crew.