Holy Mass at the Washington Monument, USA (1954, HD) 

To my eyes there is a priest wearing a Roman chasuble at 0:47, which would mean that this is indeed a Mass. You are correct that "mega Communions" were not a thing at this time. But large Masses have been for much longer and it was just that Holy Communion was never distributed in these cases. Today we are very accustomed to thinking that going to Mass necessitates the reception of the Eucharist. Another routine, like walking through the church door. However, this is an extremely modern feeling, and considering the general lack of vigilance amongst the "faithful" over their souls and their failure to admit (let alone confess) their sins, certainly not a very good one.

@@CatholicismArchiveYou are one hundred percent correct. When Pope Paul VI visited New York in the early 1960’s to speak at the UN, he celebrated Mass at Yankee Stadium. Out of the several thousand people in attendance, only 12 children were chosen to receive Holy Communion. Unfortunately, mega communions have led to sacrilegious communions by Catholics who do not practice the Catholic faith, and are not in the state of grace. Then there is the desecration of the Most Holy Eucharist by non Catholics including protestants, Jews and even Hindus who consider IT to be nothing more than “bread” or a “ Catholic cookie!” This is made worst by the reception of Holy Communion in the hand where it has been reported that the Sacred Host is often taken home and kept as a “ souvenir!” This should all be stopped immediately!

@@giovanniserafino1731.

@@CatholicismArchive I see it; you have a good eye!