The Beatles’ very existence was like a social experiment. Beatlemania answered countless questions and some no one had even thought to ask in 1964 and 1965. One of these was, “Could a pop/rock group play a stadium show?” On Aug. 15, 1965 they answered that by playing their first show at Shea Stadium.

Amazingly, no pop group had ever played a venue like that. Promoter Sid Bernstein, who died in 2013 and is credited with bringing the Beatles to America in the first place, hatched the idea of having the Beatles perform at the home of the three-year-old New York Mets.

Even though the Beatles sold out two shows at Carnegie Hall, it still seemed bizarre to assume that the Beatles could sell-out the 55,000-seat Shea. As the Wall Street Journal notes, Elvis Presley was the only other pop act to play stadiums before the Beatles, doing so in 1957. But these venues were half the size of Shea.

Any concern that the Beatles wouldn’t fill the stadium was put to rest by January 1965 (eight months before the show). The $4.50, $5 and $5.65 tickets all sold out and grossed $304,000, with the Beatles earning $180,000 of that. In today’s money, that means the show grossed $2.28 million.

There was no standard operating procedure for a rock stadium show at the time. As everyone has seen in footage of the show, the Beatles got stuck performing on a small stage over the pitcher’s mound. The crowd was so far away, with no temporary seating on the field. The sound system was also terrible.

Since this was still the era of long bills with several acts before the group, the Beatles themselves only performed for 37 minutes. They ran through 12 songs, including “Ticket To Ride” and “Help!” from the then-new Help! album. They finished up with “I’m Down.”

The Beatles played another show at Shea a year later, during their final tour and in the midst of John Lennon’s “more popular than Jesus” quote.

Despite issues with the show itself, the first show did set a standard for future generations of rock acts. Every act today performs in stadiums and they have the Beatles to thank for proving it’s possible. It’s a move that not only opened up rock acts to bigger audiences, but also gave them a chance to earn even more money.

screenshot from The Beatles YouTube video