On this day in 1965, the Beatles played Shea Stadium in New York City, before what was then a record audience of 55,000+ people.
The deafening level of the crowd noise combined with how far they were from the audience (you can see it in the clip, fans were not allowed on the field) meant nobody could hear much of anything. The Beatles could not hear each other either, so they basically had to just play and hope for the best. By the end of the show, John Lennon loses it, causing the others to crack up as well.
Here is my favorite clip from the concert, the show’s finale, “I’m Down.”