- Many millennials aren't familiar with some of the technological and cultural relics from earlier eras.
But sea monkeys, Brownie cameras, milk chutes, and Ricky Nelson?
Not so much.
The Pew Research Center defines millennials as those who are between 21 and 37 years old in 2018, on the cusp of Generation X (and including the youngest "Xennials") and followed by Generation Z. They're the largest generation so far, and they influence everything from fashion trends to office layouts.
But they don't know everything.
Below, find 23 things that for many people are fond memories — but for millennials, they're almost unheard of.
The Sperry and Hutchinson company's wildly popular Green Stamps program was one of the first ever retail loyalty programs.
Shoppers at grocery stores, gas stations, and department stores would earn the small S&H stamps of various denominations with each purchase. They could then collect the stamps in special booklets and redeem them for rewards in S&H stores or catalogs.
The Green Stamps program was especially popular in the 1960s and 1970s, although S&H has since converted its model to digital "Greenpoints." But should you happen to be stashing a physical Green Stamps booklet in your attic, you're in luck — the company is still redeeming those for gift cards.
8-inch floppy disks
Even millennials are old enough to have used floppy disks in their younger days. But few of them likely had exposure to the 8-inch behemoths that predated the 3 1/2-inch floppy disks most are familiar with.
Eight-inch floppy disks were the first variety that were commercially available, introduced by IBM in 1971. In the late 1970s, they were replaced by 5 1/4-inch disks, which were in turn superseded by the 3 1/2-inch format, which ruled until the advent of USB drives in the early 2000s.
Tab was the most popular diet soft drink of the 1970s. Known for its bright pink packaging, enigmatic name, and slight chemical aftertaste, Tab quickly dominated the sparse sugarless-soda industry upon its introduction in 1963.
Health scares contributed to Tab's demise after scientists linked the drink's sweetener, sodium saccharine, to cancer. But the real nail in coffin for Tab was the introduction of another Coca-Cola company product, Diet Coke, in 1982.
Ricky Nelson was one of America's first teen idols. He gained fame acting alongside his family in "The Adventures of Ozzie and Harriet," and in 1957, at the age of 16, he launched a music career that spawned several hit singles.
Nelson faded in popularity around the time Beatlemania hit the US, but he continued to perform until his death in a plane crash in 1985. He was inducted into the Rock and Roll Hall of Fame two years later.
While most millennials may not be aware of Ricky Nelson, they might be familiar with his twin sons Matthew and Gunnar, who in the 1990s struck hard-rock gold with their band Nelson.
Millions of Americans remember solving simple math equations on slide rules in the years before electronic calculators existed.
Users could multiply, divide, and perform other mathematical functions by sliding the middle of three strips to align with marks on the other two strips.
The introduction of the pocket calculator in the mid-1970s made the slide rule obsolete.
Before there was a McDonald's or Subway on every other corner, Horn & Hardart automats were pioneering the way Americans got their food.
Introduced around the turn of the 20th century, automats were restaurants with coin-operated vending machines from which patrons could purchase a wide array of food items, including hot coffee, salisbury steak, mashed potatoes, and huckleberry pie.
Automats were most popular during the Depression era in the northeastern US, but stayed relevant until the rise of fast-food restaurants in the 1960s.
Needing a key to roller skate
Roller skates in the 1950s and 1960s were metal contraptions you would strap around your shoes. To get them on or off, you had to adjust the straps with a key.
'In the Year 2525'
The Nebraskan folk duo Zager and Evans has been almost completely forgotten by time. But for six weeks in the summer of 1969, their song "In the Year 2525" was the most popular in America, topping the Billboard charts over acts like the Beatles and the Rolling Stones.
The eerie song describes an apocalyptic world in which mankind has become reliant on machines and technology. It resonated with people in a rapidly industrializing America, and it's no surprise the song's reign coincided with the first moon landing in July 1969.
When Ms. magazine was introduced in 1971, it was groundbreaking — a publication written and edited by women and promoting feminism and sociopolitical activism.
In some of its early issues, the magazine shed light on issues that most mainstream outlets wouldn't touch, including domestic abuse, abortion, and sexist language. Even its title was groundbreaking — it helped bring the word "Ms." into the lexicon as an alternative to "Mrs." and "Miss."
The magazine fell out of popularity in the 1980s but is still being published today.
The rope climb
Millennials were likely never subjected to the dreaded rope climb, an archaic gym-class staple of the 1980s and earlier.
One of the more bizarre fads of the 20th century came in 1975, when Gary Ross Dahl invented the Pet Rock — smooth stones packaged in a cardboard box and marketed as a maintenance-free pet.
Prior to the late 1960s, many homes came equipped with a milk chute, where milkmen could drop off bottles of fresh milk and collect used bottles.
Refrigeration and improved packaging have relegated milk delivery largely to the history books, but people of a certain age won't have trouble recalling them.
Sears Wish Books
Many Baby Boomers remember riffling through the pages of the Sears Wish Book every Christmas season and picking out the hottest toys and games of the year.
The catalog was first published in 1933 and remained a staple of the holiday season for decades. Nowadays, Sears is struggling with slipping sales, and the company is trying to cash in on shoppers' nostalgia with a revived Wish Book for the 2017 season.
Kodak's Brownie cameras were many people's gateway to home photography.
The small, handheld cameras were cheap and easy to use, enabling scores of Americans to take their first snapshots. Kodak sold millions of its Brownie 127 model between 1952 and 1967.
People who were children in the 1960s and 1970s will certainly remember Sea-Monkeys, the name given to brine shrimp that were sold as novelty pets.
Initially marketed as "Instant Life," the fad took advantage of the creatures' state of suspended animation — they would only come to "life" when the owner put them in water and sprinkled it with nutrients.
Advertisements for Sea-Monkeys were ubiquitous in comic books of the era, although some owners were disappointed to learn the actual animals didn't look anything like the humanoid creatures on the packaging.
'Duck and cover' drills
If you grew up during the early stages of the Cold War, you may have memories of performing the "duck and cover" drill in school.
The exercise comes from a 1951 short film funded by the Federal Civil Defense Administration during the Korean War, and after the Soviet Union began testing nuclear weapons in 1949.
Across the country, schoolchildren were taught that in the event of an imminent nuclear explosion, they should duck under their desks and cover their necks with their hands as a safety measure.
The great format wars
The 1960s and 1970s saw two technological battles that would define the way people consumed media.
In the earlier war, Compact Cassettes became the preferred form of portable audio over 8-tracks, which lost out because of its technical limitations and its inability to be rewound.
Then, in 1976, Sony's Betamax lost out to the VHS in a war between two videotape formats. Betamax purportedly had better video quality, but VHS won out thanks to its larger storage capacity and more lightweight machinery.
Now, both 8-tracks and Betamax have been relegated to the technological graveyard.
People who lived through the 1960s probably remember the short-lived dance craze known as "the frug."
The dance, pronounced "froog," was marked by unusual poses and exaggerated arm movements, and was one of many dances that spawned from "the twist." The frug was prominently featured in the 1966 musical “Sweet Charity."
The 1960s and '70s gave us some weird television, and there’s no better example than "H.R. Pufnstuf." The titular character was a life-size dragon who served as mayor of Living Island, a bizarre land with dancing trees, talking houses, and a magical flute.
Ostensibly a children’s show, "H.R. Pufnstuf" found a loyal following among users of marijuana and LSD thanks to its psychadelic imagery and apparent drug references (which the creators denied). Although the show only aired for 17 episodes, TV Guide named it one of the 30 top cult TV shows of all time.
'Battle of the Network Stars'
If you dreamed of watching your favorite TV actors square off in games like volleyball, tug-of-war, and Simon Says, then "Battle of the Network Stars" was the show for you. Debuting in 1976, the competition pitted actors from ABC, CBS, and NBC against each other for network supremacy.
Some of the notable competitors over the years included Farrah Fawcett, LeVar Burton, William Shatner, Billy Crystal, Lynda Carter, Heather Locklear and Michael J. Fox.
Jimmy Carter’s run-in with a swamp rabbit
In 1979, President Jimmy Carter was on a fishing trip in Georgia when a large swamp rabbit jumped into the lake and swam toward Carter's boat.
The president fended off the creature with his paddle, but his troubles were just beginning. The story was eventually leaked to the press and gave fodder to Carter's critics who saw him as weak and hapless. (It also spawned some truly delightful novelty songs.) Carter’s public image never recovered, leading writer Dave Barry to call the incident the most important moment of Carter's presidency.
One of the more regrettable culinary crazes of the mid-20th century was encasing all varieties of savory food in jello. The king of these concoctions was Jello salad, and in the 1950s and '60s it appeared on kitchen tables across America.
Serious Eats writer Sarah Grey said the dish took off because of its simplicity, convenience, and elaborate display, and dubbed Jell-O salad "the wobbling jewel of domestic achievement."
TV stations signing off
In the days before 24-hour broadcasting, TV stations would save money by going off the air in the early hours of the morning. Up through the 1980s, it was common for network sign-offs to include patriotic music, footage of local landmarks, and a thank-you message for viewers.
You can check out some memorable sign-offs here.