On this day — May 25, 1977, the Wednesday before the Memorial Day weekend — “Star Wars” opened in theaters and changed the pop cultural landscape.

Our three “Star Wars” heroes. (Lucasfilm Ltd. & TM. All Rights Reserved)

To borrow the words of a Washington, D.C. resident whose Cleveland Park neighborhood was overrun that summer with “Star Wars” fans, waiting in line over and over to see Luke, Han and Leia at the Uptown Theater: “It’s ... it’s an invasion.” (Read this whole Washington Post article about the neighborhood consternation back in ‘77. The quotes in it are a riot: “I told my wife, ‘Hey, some clown is blocking the driveway.' The funny thing is that it turned out to be a friend of my wife whose car was blocking the drive, a person who had just graduated from clown school.")

Indeed, “Star Wars” was an invasion, and not just on the once pleasantly serene streets of D.C.’s Cleveland Park. It firmly established the power of the summer blockbuster, surpassing “Jaws” as the highest-grossing movie of all time and making every studio executive in Hollywood anxious to replicate its secret Skywalker sauce. It ushered sci-fi into the mainstream. It made us believe that wearing buns on either side of your head was in­cred­ibly cool. It gave us the best movie theme song ever, and the best villain’s theme song ever, and made us giddy every time we saw words written in Franklin Gothic font soaring off into a black sky.

It also proved, without a shadow of a doubt, that Han shot Greedo first, since we saw the movie in the ‘70s and didn’t even think there would be a debate about this 20 years later when a special edition came out because, for God’s sake, Han totally shot first.

But perhaps the biggest game-changer that “Star Wars” led to is this: it created a generation of people desperate for pop culture merchandise.

As hard as this might be for young ’uns to believe, there was a time when movies were released without a cavalcade of products to accompany them. Maybe there were T-shirts here and there, a re-release of the book that provided a film’s source material (see “Jaws” or “The Exorcist”) or maybe a soundtrack. But usually, that was about it.

“Star Wars” changed all of that. Kids absolutely loved this movie and they wanted anything they could find that would allow them to recreate its universe of Stormtroopers, Death Star blow-ups and awesome singles bars on Tatooine. Thus, the action figure was born. And the radio-controlled R2D2. And a Death Star space station with a working trash compactor. Seriously, look at all this stuff Kenner successfully sold us!

There were book-and-record sets for kids who wanted to read and hear the “Star Wars” story again, in between their 178th and 179th visits to the theater to see it. There were many fast food tie-ins. (Man, I miss Burger Chef . Also, I had no idea that, per this commercial, Allison Brie’s mother once worked there.)

Inevitably, the sequels were launched, which provided us with even more junk to buy. Like “Empire Strikes Back” Underoos.

And breakfast cereal.

And video games.

And more toys, toys, toys:

Even stuffed Ewoks. (P.S. I still totally have a stuffed Wickett. P.P.S. Please don’t break into my house and try to steal it.)

Really, it hasn’t stopped since them. Any film with a potential child (or childlike) audience routinely spawns a whole line of products and commercial tie-ins to accompany its release, thanks to the precedent set by “Star Wars.” The “Star Wars” brand remains an in­cred­ibly lucrative enterprise 35 years after the first movie’s release. And we, the Generation Xers who brazenly coveted every mini-Jawa and Wookie we could get our hands on, have become adults who look back at the products from our childhoods with more wistfulness than we feel while viewing family photos.

“Oh, there’s a picture of everyone from that Christmas we spent at Grandma’s in Michigan. And — GOOD GOD, IS THAT MY MILLENNIUM FALCON UNDER THE TREE?!”

In Morgan Spurlock’s recent documentary that borrows its title from the original “Star Wars” — “Comic-Con Episode IV: A Fan’s Hope” — one of Spurlock’s interview subjects, director Eli Roth, notes that the generation raised in the ‘70s and ‘80s was the first one to hang on to all of its stuff from childhood. Why? Because that stuff gives us an identity.

If that stuff is indeed our identity, we have “Star Wars” to thank for it.