What was the biggest mistake in history?

1. That one European art school that was way too stingy with admissions.
   — Ball_Masher


2. Mao's Great Leap Forward. A disastrous attempt to modernize China, it is credited with causing the Great Chinese Famine, resulting in at least 18 million deaths from starvation, with some historians placing the number closer to 55 million deaths. https://en.wikipedia.org/wiki/Great_Leap_Forward
   — FlashpointJ24


3. Ending the reconstruction of the south too early after the American Civil War
   — arandomperson7






4. Sega Saturn's release date was moved up in an attempt to get a head start on the fall season, before the highly anticipated PlayStation was to debut. [It backfired.](https://www.theguardian.com/technology/2015/may/14/sega-saturn-how-one-decision-destroyed-playstations-greatest-rival)
   — theycallmemomo


5. Ending Club Penguin.
   — emptyzombiekilla


6. Many were increasingly of the opinion that they'd all made a big mistake coming down from the trees in the first place, and some said that even the trees had been a bad move, and that no-one should ever have left the oceans.
   — keithwaits






7. A fun one was about a monk who found some book and scraped off its contents and used it as a prayer book. They later used multi-spectrum imaging and found out that the monk scraped off the text of an unknown book by Archimedes laying down the basics of calculus thousands of years before it was invented. EDIT. I paraphrased it from a Vsauce video. But here's the [wiki article ](https://en.m.wikipedia.org/wiki/Archimedes_Palimpsest)
   — EminemLovesGrapes


8. Germany attacking Russia during World War II. Likewise, Japan attacking the United States. Both attacks created enemies that went on to annihilate the Axis. Stalin was happy to let Germany do its thing as long as it left Russia alone. If Germany hadn't split its forces and sunk its resources into getting bogged down in Russia, it would've had the full brunt of its army to resist an invasion of Europe, which would likely have prevented Overlord altogether. Japan was already winning on all fronts when it attacked the US, and vastly underestimated the thirst for vengeance of the American public and the sheer production power of the US's industries. They knew the US would grind them down in a drawn out war and, much like Germany, thought they could wipe out a massive power in a short burst. If both powers had cooled their jets and not attacked two *enormous* countries, they might have won the war. Not that I wish they had, but you can't help but facepalm at two powers that had won pretty much every battle and still had the initiative and then proceeded to *completely squander it.*
   — RaynSideways


9. When Fry chose not to bring Seymour back to life because he though Seymour lived a happy life in his absence.
   — jpterodactyl