China's Four Pests campaign is a great example. As the campaign says, China had a bit of a pest problem. One of these particular pests was the sparrow. The government decided it would be a great idea to launch an "exterminate sparrows" campaign. The only problem was sparrows ate other pests such as bedbugs and locusts.
In short, they sucessfully curbed the "sparrow problem" and replaced it with a "locusts and bedbugs problem". This ultimately upset the ecological balance and further lowered the rice yields. It was a complete disaster
We’ll there was that time Kublai Khan tried to invade Japan with the largest amphibious assault in history (until D-day) and got absolutely wrecked by a typhoon.
Then tried again a few years later, with an even larger force, and got wrecked by another typhoon.
Tan colour line from left to right is the trip from France to Moscow, 1mm line weight = 6000 soldiers, black colour line from right to left is the trip back to France. The line slowly thins and diverges like a tree branch until 422k soldiers are whittled down to 10k returning. Not quite the outcome Napoleon had intended.
King Pyrrhus of Epirus. He was known for winning battles against superior armies, at the cost of taking heavy losses. He was once quoted as saying "If we are victorious in one more battle with the Romans, we shall be utterly ruined."
He was so famous for this, that the term for a victory that devastates the victor bears his name, a Pyrrhic victory.
When the Spanish were raping the New World in the 1500s for gold, they dumped enormous quantities of platinum into the ocean because it was the wrong kind of shiny metal. Nobody in Europe had any clue how valuable the stuff was, only that it was often used to counterfeit gold. But since it wasn't gold, or even silver, everyone thought it was worthless. This was exasperated by the fact that nobody could melt the stuff until the 1800s. But mostly it was just not yellow enough for the idiots at the time.
Knight Capital - They were biggest equities trader in 2012. They manually deployed code and didn't get configuration right and it reactivated "Powder Peg". They lost $460 M in 45 minutes and went bankrupt.
Since December 1982, the O-rings had been designated a “Criticality 1″ item by NASA, denoting a component without a backup, whose failure would result in the loss of the shuttle and its crew.
Richard Feynman[:] “… [the shuttle] flies [with O-ring erosion] and nothing happens. Then it is suggested, therefore, that the risk is no longer so high for the next flights. We can lower our standards a little bit because we got away with it last time. You got away with it, but it shouldn’t be done over and over again like that.”
Elon acquiring Twitter for $44B in the first place, not taking into account the subsequent blunders. He not only overpaid too much for a social media company without even understanding it, he also wrecked Tesla's stock price as investors saw he was clearly spending too much time on Twitter and he had to panic sell Tesla shares to fund his Twitter adventure. He easily wiped out hundreds of billions from Tesla's market cap during that time.
The Gunpowder Plot. Guy Fawkes and his friends were about to blow up parliament, and on the week it was supposed to happen, one of his accomplices sent a letter to a noble. In what was probably the worst example of "asking for a friend" in history, it asked "hypothetically, what would happen if someone went into the basement and blew up parliament". The noble did what nobody expected he would do and, get this, responded to the letter. People searched the palace basement and found Guy Fawkes, he was arrested and killed, and we have Guy Fawkes Day. The reason this led to a loss is because the king of England at the time used it as an excuse to persecute Catholics and make the holiday which is used as a taunt.
Russia invasion of Ukraine. They used to be number 2 army with sophisticated weapons. Now they are number 1 world laughing stock with weapons that works exceptionally well for invading Mars but not on earth.
I'm willing to nominate Charles II, King of Spain as a formerly alive blunder. The result of decades of Hapsburg inbreeding, he had a number of health and intellectual issues from birth and he was notably infertile. If you live in a monarchy where succession is passed down through children, it's REALLY BAD to be infertile and be King. His death directly caused the War of the Spanish Succession, a 13-and-a-half year war that eventually involved pretty much all of western Europe and likely led to the deaths of over 1 million people.
Literally could have avoided this if the Habsburgs decided to have sex with other people.
In terms of money and business, my fav is how Xerox didn't know how to market/capitalize on what was effectively the first personal computer before personal computers were even a concept, which is estimated to be a $1.4 trillion mistake.
Long-Term Capital Management was a hedge fund founded in 1994 that had notable academics and Nobel Prize winners on its board. It was very successful in the early years (while critics warned of the risks) and eventually collapsed in 1998, losing $4.6 billion in a matter of months due to its leverage and impacts of currency crises. The US government stepped in to shore up the financial system. It's taught as a case study in how a strategy can post impressive returns but quickly turn into a wipeout.
King Mansu Musa was incredibly rich and when he went on hajj to mecca he spent much of his gold in Egypt causing a massive inflation. On his way back to Mali this has caused him needing to spend much more this time on his route through Egypt which is why he needed loans from merchants.
Okay, I listen to a fair amount of history podcasts, so let's see what I can pull out of my head for fun:
There was Rainbow Man, who famously went to sports games across America, holding up a sign that read "John 3:16" in an attempt to convert people to Christianity. He later died in a hotel shoot out where he took a maid hostage in his hotel room full of guns.
There was the time the President of America secretly went on a trip to Panama on one of two ships. While trying to show off to the president doing drills, the other ship accidentally shot a torpedo at the presidents ship. He pulled a pistol and attempted to shoot the torpedo with it.
The settlement at Roanoke, which was one of the earliest attempts by Europeans to settle in America and by the time ships got back with supplies (I believe years after they said they would be back) the settlement was empty. Still unsolved to this day.
America has dropped at least two nuclear warheads on itself accidentally, which have all failed to detonate.
Benedict Arnold was one of the best military minds ever born in America. He paid for his own troops for years, and when he asked for repayment or even his own salary, the Republicans claimed he actually owed the government money. They gave him tje reputation of only caring about money and refused to ever pay him until he finally took money from Britan to make ends meet.
George Bush senior crashed into German electrical lines and flew the plane back to base causing an international incident. He never received punishment for this and continued to fly for the military. He also did a bunch of drug smuggling and no one cared.
Look into pretty much any time people wanted to explore an area for the first time and there was most likely a massive loss of life and money. Australia and America seem to have the funniest stories of people's attempts to name every river and mountain they see.
Cambium stock recently dropped to $10 after the CEO stepped down during their call. A large part of their problems are likely due to the pandemic shortages catching up.
But a high failure rate on their new line of switches, and high prices while starlink eats their lunch isn't helping.
Any history book will be filled with such stories. Depending on the outlook, I'd say all history is like that.
Take any one event. Let's pick any decisive moment in history. Say, the battle of Salamis. Now flip it to the side of the Persians and you have the kind of blunder you're looking for.