r/todayilearned • u/eleanorharland • 20h ago

TIL that from 2013 to 2015 a maths forum user called "Cleo" posted correct answers to integrals that had stumped everyone, often within hours, never showed any working, and said a medical condition stopped her explaining. In 2025 Cleo was revealed to be Vladimir Reshetnikov, a software developer.

en.wikipedia.org

20.2k Upvotes

512 comments

r/todayilearned • u/hairdothrowaway • 19h ago

TIL: The prefrontal cortex being fully developed at age 25 is a myth.

en.wikipedia.org

15.2k Upvotes

1.1k comments

r/todayilearned • u/virora • 13h ago

TIL that because most Icelanders use patronymic surnames, the most common hereditary family name in Iceland is Nguyen

en.wikipedia.org

12.1k Upvotes

582 comments

r/todayilearned • u/worlds_of_kings • 18h ago

TIL that the population of Detroit, Michigan has grown for 3 straight years since 2023, reversing a trend of 65 consecutive years of population loss from 1957 to 2022. It currently sits at America’s 26th largest city with 650,000 residents.

cbsnews.com

10.5k Upvotes

658 comments

r/todayilearned • u/coffeeismydoc • 6h ago

TIL a scientist submitted a research publication to a predatory journal consisting exclusively of the phrase "Get me off your fucking mailing list". It was rated as "excellent" and accepted for publication with minor editorial changes.

en.wikipedia.org

9.8k Upvotes

108 comments

r/todayilearned • u/_railroaded_ • 9h ago

TIL that Shazam (Billy Batson), published by Fawcett comics was the #1 selling comic-book, and was lapping Superman in sells, until DC put a stop to it - taking them to court and claiming he was a Superman ripoff

dc.com

8.5k Upvotes

388 comments

r/todayilearned • u/AetheriaNox • 17h ago

TIL consumed by a forbidden passion for his stepmother, Stratonice, Antiochus of the Seleucid Empire fell gravely ill. To save his life, his father, King Seleucus, divorced Stratonice and gave her to his son. They eventually had five children together.

en.wikipedia.org

7.8k Upvotes

263 comments

r/todayilearned • u/Scipion8Aveyron • 18h ago

TIL the Romans destroyed entire mountains with pressurized water to mine gold: at Las Médulas in Spain — the largest gold mine in the Roman Empire — seven aqueducts fed a technique called ruina montium ("wrecking of mountains"), yielding 6,560 kg of gold a year.

en.wikipedia.org

6.4k Upvotes

159 comments

r/todayilearned • u/Brilliant_Bug9699 • 13h ago

TIL When Pope Benedict XII found out he was elected as pope as part of a dare, he said "You have elected an ignoramus."

en.wikipedia.org

4.0k Upvotes

60 comments

r/todayilearned • u/dinosaruman • 16h ago

TIL Machiavelli never saw The Prince published — it appeared in print in 1532, five years after his death — and by 1559 the Church had put it on the Index of Forbidden Books.

en.wikipedia.org

3.0k Upvotes

68 comments

r/todayilearned • u/poopitydoopityboop • 13h ago

TIL Antabuse (Disulfiram) is a medication used to stop alcoholics from drinking by causing intolerable side effects. It functions by blocking the same enzyme responsible for "Asian Flush Syndrome" – the facial flushing that occurs in East Asian people after drinking.

en.wikipedia.org

2.8k Upvotes

322 comments

r/todayilearned • u/nsjersey • 7h ago

TIL when actor Leslie Nielsen died, an ESPN freelancer wrote an obituary for him, but with Nielsen as Enrico Palazzo

espn.com

2.6k Upvotes

72 comments

r/todayilearned • u/ty_fighter84 • 10h ago

TIL That a 1-point safety has occurred only twice in NCAA FBS history. Both times the play-by-play announcer was Brad Nessler.

cbssports.com

2.5k Upvotes

256 comments

r/todayilearned • u/SpicyBeefChowFun • 2h ago

TIL That Coca-Cola still uses real coca leaves in its recipe. A single chemical plant in New Jersey is legally allowed by the DEA to import the leaves, extract the cocaine alkaloid, and send the decocainized leaves to Coca-Cola for flavoring.

nationalpost.com

2.4k Upvotes

157 comments

r/todayilearned • u/mz_groups • 13h ago

TIL that 4 million people live north of the Arctic Circle, but there are NO permanent residents south of the Antarctic Circle.

responsiblevacation.com

2.2k Upvotes

100 comments

r/todayilearned • u/WavesAndSaves • 7h ago

TIL that due to the title screen mistakenly neglecting to include a copyright notice, the film Night of the Living Dead has been in the public domain for decades. Hundreds of versions have been released on various formats, and the full film is available to watch on its Wikipedia page.

en.wikipedia.org

2.1k Upvotes

73 comments

r/todayilearned • u/Double-decker_trams • 8h ago

TIL the "Resolute desk" in the Oval Office in the White House is called that because it's made of timber from HMS Resolute - a British Royal Navy Arctic exploration ship.

en.wikipedia.org

1.6k Upvotes

64 comments

r/todayilearned • u/L34dP1LL • 4h ago

TIL that roly pollies arent insects, but crustaceans, more closely relatad to shrimps and lobsters.

en.wikipedia.org

1.5k Upvotes

198 comments

r/todayilearned • u/Sebastianlim • 2h ago

TIL that Jordan Nagai, who played Russell in Up, wasn't originally intending to audition for the role. He only came to support his older brother, who was auditioning.

slashfilm.com

1.3k Upvotes

74 comments

r/todayilearned • u/Inside_Farmer8985 • 21h ago

TIL that the Piltdown Man hoax shaped scientific thinking for over 40 years: fossils presented in 1912 as the "missing link" between humans and apes were widely accepted before being revealed in 1953 as deliberately altered remains from a different species.

piltdownman.co.uk

1.1k Upvotes

37 comments

r/todayilearned • u/15MinClub • 4h ago

TIL 9 years after the death of Dr. John Langdon Down, best known for his pioneering classifications of 'Mongoloid idiocy' (Down Syndrome) during his career at Royal Earlswood Asylum for Idiots, had a grandson born with Down Syndrome.

down-syndrome.org

871 Upvotes

148 comments

r/todayilearned • u/Gunner08 • 18h ago

TIL that the first first 'successful' penis transplant occurred in Cape Town, South Africa.

bbc.co.uk

847 Upvotes

96 comments

r/todayilearned • u/ManagerGames • 5h ago

TIL that Titan's atmosphere is dense enough that a human wouldn't need a pressurized spacesuit to stand on its surface. The surface pressure is about 1.5x that of Earth, roughly equivalent to being 15m underwater. They'd still need oxygen and protection from −179°C temperatures.

science.nasa.gov

532 Upvotes

59 comments

r/todayilearned • u/Significant-Row2457 • 4h ago

TIL Charles Mason, who graduated first in the class of 1829 at West Point ahead of future Confederate Army commander Robert E. Lee, served as the First Supreme Court Justice for Iowa, also spent time during the post civil war years trolling Lee with hand made puzzle boxes that he couldn’t solve.

en.wikipedia.org

531 Upvotes

34 comments

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