In 2020, we’ll be marking many significant pop culture anniversaries, from the Beatles breaking up (50!) and ’N Sync breaking out (20!) to significant dates for superstars like Billy Joel, Jerry Seinfeld and Mariah Carey. Here’s a list of notable anniversaries designed to make you say out loud, “I can’t believe it’s been that long!”


1970 (50th anniversary)


“Patton” (April 2): Perhaps the Variety critic said it best about this biopic about the legendary general: “War is hell, and ‘Patton’ is one hell of a war picture, perhaps one of the most remarkable of its type ever made.”


Jimi Hendrix’s death (Sept. 18) and Janis Jopin’s death (Oct. 3): In just 15 days, drug overdoses take two of rock’s most dynamic performers.


“The Mary Tyler Moore Show” debuts (Sept. 19): One of TV’s greatest ensemble casts, led by Moore as Mary Richards, a proudly single woman with a career (and spunk). Hard to believe, but such a concept was groundbreaking for TV in 1970.


“NFL Monday Night Football” debuts (Sept. 21): In the first game, Joe Namath and the Super Bowl champion Jets played the Browns in Cleveland. The Jets lost.


The Beatles break up (Dec. 31): The long and winding road reaches its inevitable end as Paul McCartney files a lawsuit against the other three members asking that the band be legally dissolved.


1980 (40th anniversary)


CNN launches (June 1): All news all the time on the tube? Skeptics called Ted Turner’s new channel the “Chicken Noodle Network” and said the concept would never work.


Billy Joel’s “It’s Still Rock and Roll Me to Me” hits No. 1 (July 19): The Piano Man’s first chart-topper was a put-down of New Wave poseurs.


“Caddyshack” (July 25): Who knew the country-club farce starring Bill Murray, Rodney Dangerfield and Ted Knight would become a cult classic?


The resolution of the “Who Shot JR?” episode on “Dallas” (Nov. 21): The biggest TV audience to date tunes in to see whodunit (spoiler alert for those coming extremely late to the party: it was Kristin).


John Lennon murdered (Dec. 8): In the era before social media, most Americans first heard the sad news from Howard Cosell during “Monday Night Football.”


1990 (30th anniversary)


“U Can’t Touch This” (Jan. 13): Hammer Time commences as former Oakland A’s batboy M.C. Hammer samples Rick James’ “Superfreak” and has the first rap song to be nominated for a record of the year Grammy.


“Twin Peaks” (April 8): David Lynch’s s surreal TV series came back with a head-scratching update in 2017, but the original stretched the boundaries of primetime drama like nothing before it, until spectacularly flaming out.


“Seinfeld” (May 31): Almost a year after its pilot aired, the show about nothing gets picked up for four episodes on the NBC sked thanks to a network executive who saw the show’s potential. The initial episode is noteworthy for being the first time the name “Art Vandelay” is mentioned.


Mariah Carey’s debut (June 12): The Harborfield grad’s self-titled album is released, and would go on to yield four No. 1 singles (including “Vision of Love” and “Love Takes Time” in 1990) and spend 11 weeks at the top of the charts.


“Home Alone” (Nov. 16): Macaulay Culkin will turn 40 this year, but in our mind he’s always going to be 8-year-old burglar-basher Kevin McAllister.


1995 (25th anniversary)


“Star Trek: Voyager” (Jan. 16): The fourth in the TV franchise (and the first with a female captain) was the centerpiece of UPN, a new (and ultimately doomed) broadcast network.


Selena killed (March 31): The world’s most popular Tejano singer was shot to death by her former personal assistant in Corpus Christi.


“Clueless” (July 19): The movie, adapted from a Jane Austen novel and set in Beverly Hills, Calif., became a hit and a star-making vehicle for Alicia Silverstone.


Jerry Garcia’s long strange trip ends (Aug. 9): The spiritual and musical leader of the Grateful Dead died of a heart attack in his room at a California rehab facility.


“Toy Story” (Nov. 22): Woody and Buzz become pop culture icons, Don Rickles finds a new audience as the voice of Mr. Potato Head, and computer-generated animation comes of age.


2000 (20th anniversary)


Y2K fears subside (Jan. 1): That sound you heard was the world breathing a collective sigh of relief that we were not tossed back into the Stone Age.


’N Sync breaks out (March 21): Justin Timberlake and his boys set the one-week Nielsen Soundscan sales high of 2.4 million with their album “No Strings Attached.” It sells 1 million the first day, 9 million by year’s end.


“Oops … I Did It Again” (May 16): Britney Spears’ second album turns the 19-year-old ex-Mouseketeer into a pop icon.


“Survivor” (May 31): The reality era begins on network TV. A few months later, 51 million viewers will watch the first season finale. Richard Hatch, a scheming corporate trainer, took home the $1 millon prize and later went to jail for failing to pay back taxes on those same winnings.


“CSI: Crime Scene Investigation” (Oct. 6): Gil Grissom and Co. crack their first case.


2010 (10th anniversary)


“Jersey Shore” (Jan. 7): The MTV reality show had actually debuted a month earlier, but grew into a pop-culture colossus in 2010 on the strength of episodes like the one that aired this night: “When Mike invites girls back to the house, the situation gets out of control, and Snooki gets into her second fight of the summer. Meanwhile, Ronnie gets into a brawl of his own, leaving Sammi questioning their relationship …”


“Lost” finale (May 23): We’re still trying to figure out what happened.


Lady Gaga wears a meat dress to the VMAs (Sept. 12): Vegetarians everywhere recoil in horror.


“The Social Network” (Oct. 1): In this biopic, Jesse Eisenberg plays Facebook founder Mark Zuckerberg as the social media site seems an unstoppable force for good.


Nicki Minaj breaks through (Nov. 19): The Trindad-born, Queens-raised rapper’s debut album “Pink Friday” is released, capping a year in which she performed at Yankee Stadium and became the first female solo artist to have seven songs on the Billboard Hot 100.