History's Most Expensive Mistakes: 7 Blunders That Cost a Fortune

Everybody makes mistakes. A few people make mistakes so large that historians are still writing about them centuries later. The good news is that the big ones tend to follow a small number of patterns, which means they are unusually good teachers.

Here are seven well documented blunders. Where costs are involved, I have kept to qualitative descriptions or widely reported estimates, because many popular figures floating around online are guesses dressed up as facts.

1. Tulip mania, 1630s

In the Dutch Republic of the 1630s, prices for rare tulip bulbs rose to remarkable levels, especially for the striped varieties whose flames, we now know, were caused by a virus. Much of the late trading happened in taverns, using contracts for bulbs still in the ground. In early 1637 buyers stopped showing up, and prices collapsed.

Modern historians argue the damage was narrower than legend claims. The wider Dutch economy kept growing, and many contracts were settled for a fraction of their value. But as a lesson in buying something because others are buying it, it remains unbeatable. We tell the full story in tulip mania explained, and MindSnap's Tulip Fever collection turns it into a narrative expedition. Disclosure: MindSnap is our app.

2. The Vasa, 1628

The Vasa was meant to be the pride of the Swedish navy: heavily armed, lavishly carved, built at the command of King Gustavus Adolphus. On 10 August 1628, in Stockholm harbour, she set sail on her maiden voyage, heeled over in a light gust, took on water through her open gunports and sank. She had travelled only a short distance.

The ship was top heavy, carrying too much weight high up and too little ballast below. A stability test before launch reportedly showed the problem, yet the voyage went ahead. Nobody wanted to tell the king his ship did not work. She was raised in 1961 and now sits in her own museum, perhaps the most beautiful monument to a skipped warning ever built.

3. The Leaning Tower of Pisa, begun 1173

Construction of Pisa's bell tower began in 1173, and it started to tilt after the first few storeys went up. The cause was simple: soft, uneven soil beneath a shallow foundation. Work paused for long stretches, partly because of wars, which gave the ground time to settle and probably saved the tower from collapse. Later builders tried to compensate by making upper storeys slightly curved.

Here is the twist: the mistake became the attraction. Engineering work in the late twentieth and early twenty first centuries reduced the lean to make it safe, while deliberately keeping it tilted. Few errors pay for themselves in tourist tickets.

4. The Louisiana Purchase, 1803

In 1803 France, under Napoleon, sold the Louisiana territory to the United States for around fifteen million dollars, roughly doubling the young country's size. From France's perspective, the sale is often cited as a spectacular underpricing.

In fairness to Napoleon, he had reasons. France had struggled to hold its colonial ambitions in the Caribbean, war with Britain was looming, and he needed money more than land he could not defend. Calling it a mistake is partly hindsight. Still, few land deals in history look quite as lopsided when you view them from the seller's side of the table.

5. Decca passes on the Beatles, 1962

On New Year's Day 1962, a little known Liverpool band auditioned for Decca Records in London. Decca declined and signed another group instead. The band's manager kept knocking on doors, and later that year they signed with EMI's Parlophone label. They were, of course, the Beatles.

The quote usually attached to the rejection, that guitar groups were on their way out, is widely repeated but its exact wording is hard to verify, so treat it as folklore. The business misjudgment itself is well documented. In fairness, Decca later signed the Rolling Stones, reportedly on a tip from George Harrison, which is a decent way to recover.

6. The Hubble mirror, 1990

The Hubble Space Telescope launched in 1990 with enormous expectations. Its first images were disappointingly blurry. The primary mirror had been ground to the wrong shape, off by a tiny fraction of the width of a human hair at the edge. A testing instrument had been set up slightly wrong, and warning signs from other tests were discounted.

The fix required a shuttle servicing mission in 1993 that installed corrective optics, essentially glasses for the telescope. It worked brilliantly, and Hubble went on to become one of the most productive scientific instruments ever. But the repair was costly, and the error was a textbook case of trusting one measurement over several that disagreed.

7. The Mars Climate Orbiter, 1999

In September 1999 NASA's Mars Climate Orbiter approached Mars far too low and was lost. The investigation found that one piece of ground software produced thrust data in imperial units, pound force seconds, while another expected metric newton seconds. Small navigation errors accumulated over the months long trip.

The mission cost was widely reported at well over a hundred million dollars. The deeper cost was embarrassment: the kind of mistake a school physics teacher warns about, missed by professionals because each team assumed the other had checked.

What these blunders have in common

Look past the details and familiar patterns appear.

• Overconfidence. The Vasa's builders, Hubble's testers and the tulip buyers were all sure they had it right.
• Ignored warnings. Several of these stories include a test or a doubt that someone quietly set aside.
• Handoff gaps. The Mars probe fell between two teams, each assuming the other owned the check.
• Optimistic plans. Schedules, budgets and prices assumed the best case. This is the planning fallacy at work, the tendency to underestimate time, cost and risk even when past experience says otherwise.
• Hindsight. Some mistakes, like the Louisiana sale, look worse now than they did at the time, which is a reminder to judge decisions by what was knowable.

Mistakes are rarely as simple as they look, and not every famous one is true. For the ones that were invented outright, see history's greatest hoaxes. For errors that accidentally went right, try accidental discoveries that changed the world.

Learning from other people's disasters

The cheapest way to learn from a mistake is to learn from someone else's. MindSnap is our app, an iOS micro learning app with two minute daily lessons, five flagship story driven collections and unlimited topics. Its Turning Points feature asks you to make the call at moments like these before revealing what happened. It is surprisingly humbling to discover you would have launched the Vasa too.

Expensive mistakes are rarely made by fools. They are made by capable people who stopped checking.