Just after 9 p.m. on Aug. 15, 1965, the Beatles stood on a stage just off second base at Shea Stadium, and obliterated any sense of what the words "rock concert" meant.

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Here are some fun, mind-boggling, I-was-born-in-the-90s-and-will-never-truly-know-what-Beatlemania-was-like facts about the show:

1. With 55,000 fans in attendance and more than $300,000 made, it was said to be the largest concert ever at the time.

2. It seems laughable now, but there were doubts that the Beatles would be able to fill the Mets' ballpark -- "We don't play to empty seats," the Beatles' manager, Brian Epstein, had said when the show was first booked, according to the NY Daily News. But that was … not a problem. The Mets were in the middle of a West Coast road trip that ran from Aug. 10-18, and Shea Stadium was filled to the brim. People were crawling over the outfield fence to get in.

3. EVEN A TEENAGE MERYL STREEP WAS THERE.

4. The New York Times tried to get poetic when describing the reaction the Beatles pulled from the crowd:

"Their immature lungs produced a sound so staggering, so massive, so shrill and sustained that it quickly crossed the line from enthusiasm into hysteria and was soon in the area of the classic Greek meaning of the word pandemonium -- the region of all demons."

The roar of the audience drowned out all other sound, including the Beatles themselves:

"The fans drowned out almost all the singing. Little more than the pulsation of the electric guitars and thump of drums reached the stands..."

5. "It might as well have been a silent movie," The Daily News wrote of the opening act. To try to compensate, sound was pumped through Shea Stadium's PA system.

6. That same NYT article reported that fans were begging police to give them blades of grass from the parts of the field that the Beatles had walked on. Sure, fans at Shea probably begged for the grass Tom Seaver walked on too, but that wasn't until a few years later.

7. When the Beatles were asked in a pre-show press conference who the band's most enthusiastic fans were, John Lennon responded, "The ones that are nearest." Apparently "nearest" meant anyone within the confines of the 57,333-seat Shea.

8. Naturally, the Beatles used the Shea facilities (including the clubhouse) to get ready for the show. Think about the people who've gotten changed in that clubhouse: Nolan Ryan, Doc Gooden, George Harrison.

9. Ed Sullivan had the whole thing filmed and released it in the U.S. as a made-for-TV documentary a year and a half later.

10. Shea Stadium no longer exists. So, as part of the nostalgia bridge-building between Shea and Citi Field, Paul McCartney played Flushing almost 44 years after he first made an appearance with the Beatles. Things were slightly different in 2009, though -- according to the NYT review: "Of course, Mr. McCartney wasn't about to return to the primitive conditions of a 1965 Beatles show ..."