5TH Occupy Wall Street
Inspired by the Arab Spring, hundreds of people went to lower Manhattan to decry economic and social inequality. Some lawsuits over the treatment of protesters continue to make their way through courts.
Also turning 5: Anthony Weiner’s resignation from Congress
10TH First tweet
Twitter co-founder Jack Dorsey made social-media history with the very first tweet: “Just setting up my twttr.” The message has been retweeted more than 66,000 times.
Would have turned 10: The marriage of Tom Cruise and Katie Holmes (had it lasted)
15TH Same-sex marriage in the Netherlands
Fifteen is the crystal anniversary, so raise a flute to the Dutch couples who took advantage of their nation’s being the first to legalize same-sex marriage.
Also turning 15: Wikipedia
20TH Garry Kasparov’s victory over Deep Blue
The human chess champ’s victory over his robotic opponent was short-lived, however, as an upgraded Deep Blue triumphed in a rematch the following year.
Also turning 20: “Wannabe” by the Spice Girls
25TH Nirvana’s Nevermind
The gods of grunge defined the feel of the ’90s with this surprise hit album. Its Gen X anthem “Smells Like Teen Spirit” landed on TIME’s list of the 100 greatest songs ever.
Also turning 25: The Silence of the Lambs (the movie)
30TH Chernobyl reactor explosion
Time’s cover that week featured a one-word headline: “Meltdown.” The accident in Ukraine remains the most devastating in nuclear history, and Chernobyl is still synonymous with disaster. Recently, remote cameras have captured wildlife flourishing in the fallout zone.
Also turning 30: NASA’s Challenger disaster
40TH Apple Computer Co.
Use an iPhone to tell your friends that you’re glad Steve Jobs, Steve Wozniak and Ronald Wayne turned their tinkering into a business.
Also turning 40: Taxi Driver
50TH Star Trek
The first episode, “The Man Trap,” in which Captain Kirk faces an alien desperate to suck the salt out of human bodies, was panned by many critics. In retrospect, they perhaps did not go boldly enough.
Also turning 50: Pet Sounds by the Beach Boys
60TH Eurovision contest
The brainchild of an international group of broadcasters, the showdown was more notable for its technological victories–some 4 million TV sets tuned in–than for the now forgotten winning song. (It was a Swiss entry, “Refrain.”)
Also turning 60: The Suez crisis
75TH Pearl Harbor attack
FDR’s prediction holds true: the date lives in infamy, three-quarters of a century later.
Also turning 75: The death of Virginia Woolf
80TH Jesse Owens’ four gold medals at the Nazi-hosted 1936 Olympics
Hitler intended the Berlin Games to put Aryan athletes on literal pedestals. African-American Owens, the first U.S. Olympian to win four gold medals in track and field at one Olympics, thwarted the dictator’s plan.
Also turning 80: Gone With the Wind (the book)
90TH Winnie- the-Pooh
The famous bear had popped up in previous works by author A.A. Milne, but the first collection of stories in which he starred made Winnie a household name. He lost his hyphens after Disney acquired the rights to the character.
Also turning 90: The anniversary of Marilyn Monroe’s birth
100TH First woman in U.S. Congress
Representative Jeannette Rankin of Montana made history as the first woman elected to the House, four years before women were guaranteed the right to vote nationally by the 19th Amendment.
Also turning 100: U.S. National Park Service
This appears in the December 28, 2015 issue of TIME.