13 Dumbest Mistakes That Changed the World Forever

Welcome to WatchMojo, and today we’ll be looking at the most foolish, yet deeply consequential mistakes throughout human history.

Space Shuttle Challenger Disaster

Space, the final frontier, is notoriously difficult to explore. While several ventures into the cosmos have achieved groundbreaking success, some have yielded the exact opposite. The most devastating and high-profile disaster was the Space Shuttle Challenger in 1986. Numerous delays motivated NASA to ignore engineers’ warnings about faults in the shuttle. The result was a horrendous explosion that occurred only 73 seconds after liftoff. It remains one of America’s worst space disasters, as all seven crew members, including schoolteacher Christa McAuliffe[a], died on board. The catastrophe was traced to a failure in the shuttle’s rubber O-rings, which became stiff in the cold weather. Engineers foresaw this issue, but all they could do was watch the horror unfold from a distance.

Alexander the Great’s Successor

One of humanity’s most renowned conqueror-rulers, Alexander of Macedon[b] was the greatest king of his era. He rose to power in northern Greece and built one of history’s largest empires, which encompassed regions from Greece all the way to India. However, his untimely death at 32 marked the beginning of chaos. On his deathbed, Alexander instructed that his land be given “to the strongest,” which led to the Wars of the Diadochi, conflicts among his successors that lasted 41 years. This blunder shattered the empire’s unity and its potential for longevity. A well-planned succession could have preserved Alexander’s legacy and ensured stability, but the lack of precedent in managing such vast territories left little guidance for avoiding such a crisis.

Russia Invades Ukraine

In February 2022, Vladimir Putin made the massively unpopular decision to invade Ukraine. He and Russian leaders likely expected a swift victory, with Kyiv[c] falling in a few days and Ukraine’s government collapsing. In reality, Ukraine’s military was bolstered by fierce civilian resistance and substantial international aid, which allowed them to mount a formidable defense. The invasion was intended to weaken NATO’s influence in Eastern Europe, but it backfired. Instead, it only served to galvanize NATO and unite the international community against territorial aggression. Russia’s economy has since stagnated and the global condemnation of the invasion has only continued to grow. This was a gross miscalculation of Ukraine’s resilience, and a textbook example of a poorly planned strategy with disastrous consequences.

The Maginot Line[d]

France built a heavily fortified defensive line along their German border in the 1930s, known as the Maginot Line. It featured bunkers, tunnels, artillery, and overwhelming defenses to repel any invasion. There was one critical flaw, however: it didn’t extend to the French-Belgian border. France assumed Germany wouldn’t attack through the Low Countries, as that area was deemed impenetrable, but as you may know already, that is exactly what they did. German Blitzkrieg tactics were extremely effective, and made short work of Belgium and the Netherlands, enabling them to conquer France in just six weeks. Military minds like Charles de Gaulle had opposed the Maginot Line, arguing to invest in mobile defenses instead, but French leadership ignored the ideas, ultimately causing their downfall.

Mao’s Great Leap Forward

By the time Mao solidified control of China, the country had endured a century of humiliation. It began with the First Opium War, and things only went downhill from there. In the 1950s, Mao sought to repair and industrialize China. To do so, he launched the Great Leap Forward, a campaign to modernize the nation’s economy. Unfortunately, this policy was too ambitious for its own good, and it resulted in the Great Chinese Famine, one of the largest famines in history. Mao ruled with an iron fist, which left his advisors too scared to even report the immense failure of his policies. As a result, the catastrophe went unchecked for years, and China wouldn’t fully recover for decades.

Soviet Invasion of Afghanistan

The Soviet Union frequently made misguided decisions. One of their many disastrous geopolitical blunders was the invasion of Afghanistan in late 1979. Similar to Russia’s invasion of Ukraine, Soviet leaders assumed it would be a quick and easy war, but in reality, they got the opposite. The Soviet-Afghan War dragged on for nearly 10 years, with intense resistance from Afghan guerrilla fighters. Dubbed “the Soviet Union's Vietnam,” it resulted in over a million casualties, most of which were civilians. The conflict also became a rallying point for Islamist fighters, eventually giving rise to al-Qaeda and emboldening extremists all around the world. It was a disastrous decision, and its effects continue to shape global events today.

Guadeloupe[e] Conference: Fall of Shah

In 1979, Western leaders met in French Guadeloupe, where they decided to withdraw their support for Iran’s Shah, a pro-Western monarch and longtime ally. This lack of support emboldened opposition forces and the Western leaders failed to foresee the ramifications of their decision. Instead of a democratic replacement, the power vacuum was filled by Ayatollah Ruhollah Khomeini and revolutionary Islamist forces. Ironically, the U.S. played a key role in installing the Shah back in 1953 through a coup that overthrew Iran’s democratically elected leader, Mohammad Mosaddegh. With such a history of destabilizing Middle Eastern nations, one can’t help but wonder: would the region be more peaceful today had the U.S. never interfered?

Bush Invading Iraq[f]

In the wake of the September 11th terror attacks, tensions in America were high, with President George W. Bush declaring a war on terror. In 2003, this turned into an American invasion of Iraq, justified by claims that the nation possessed weapons of mass destruction. These claims were later found to be false, severely damaging U.S. credibility. Saddam Hussein’s regime was successfully toppled, but unfortunately, there was no coherent plan for reconstructing Iraq, which plunged the nation into chaos. The resulting power vacuum led directly to the rise of ISIS, furthering turmoil in the Middle East. Thousands of military personnel lost their lives in this senseless war, as did over a hundred thousand civilians.

Spanish Armada’s Failed Invasion

The Spanish Armada of 1588 was King Philip II’s ambitious attempt to invade England and overthrow Queen Elizabeth I. He assembled a massive fleet of 55,000 men and large warships, believing this would ensure his victory. However, he failed to foresee the innovative tactics the English would mount. English commander Francis Duke relied on smaller, faster ships and employed hit-and-run strategies to harass the Spanish fleet, before they could even get to England. But their defeat came not from combat alone, but also from bad weather. Severe storms scattered the Spanish fleet as it attempted to regroup, and many ships were wrecked as they attempted to flee through Scotland and Ireland. In the end, only a fraction of the Armada made it back home.

Napoleon’s Invasion of Russia

By 1812, Napoleon had much of Europe under his thumb. He imposed the Continental System, a trade embargo against Britain, which he compelled European states to enforce. However, when Russia defied this, The Little Corporal assembled the Grande Armée[g], a force of roughly 600,000 men to invade. At the time, armies typically sustained themselves through foraging and received payment only at the end of campaigns. But the Grande Armée was far too large to survive this way, especially as the Russians began burning their countryside to deny them resources. Napoleon’s biggest mistake was advancing on Moscow with winter approaching. When he arrived, the city had been burned, forcing him to begin one of history’s most catastrophic retreats. Ultimately, only about 100,000 men survived.

Harsh Terms on Germany After WW1

The primary cause of the First World War was a complicated web of alliances between European empires. While these alliances were intended to deter aggression, they had the opposite effect, escalating tensions between the countries and contributing to the outbreak of war. Once the conflict ended, the victors were eager to point the finger at someone, and they zeroed in on Germany. They forced Germany to accept full responsibility for starting the war, which was a major oversimplification of its causes. This not only humiliated and weakened Germany, but also fostered resentment among its people. Ironically, the treaty seeking to prevent a future war did the opposite, laying the foundations for the outbreak of World War II, just two decades later.

Angering Genghis Khan

The Mongolian Empire was the second-largest empire to ever exist. As you might expect, they didn’t achieve this peacefully. In 1218, the founder of this kingdom, Genghis Khan, sent a merchant caravan to the Khwarazmian[h] Empire in Central Asia. The two were on amicable terms, but once the group arrived in the city of Otrar, the local governor made a disastrous move. He had the traders executed and confiscated their goods, an action as insulting as spitting in the Khan’s face. Enraged, Genghis temporarily halted his war against the Jin dynasty in China, and within just two years, wiped the Khwarazmian Empire off the face of the Earth.

Hitler Invading Russia

The majority of Hitler’s ideology was fundamentally misguided. One of his major beliefs was that he and his people were superior to all other races, a seriously flawed and harmful concept. He despised both communism and the Slavic people. Hence, he was confident he could easily subdue the Soviet Union, and launched a full-scale invasion in June 1941. As many could have predicted, his ideology was proven wrong, with the invasion backfiring spectacularly. The Soviets were remarkably resilient, and it turned into the costliest mistake in German military history. Around 30 million died on the Eastern Front, approximately half of all casualties in the entire conflict.

What do you think was the most impactful historical mistake, with the least amount of thought put into it? Let us know in the comments!

[a]krista mick-CALL-iff https://youtu.be/k_ht3IUuCoU?t=11

[b]MASSA-dawn https://forvo.com/search/Macedon/
dye-ADDA-key https://forvo.com/search/diadochi/
[c]keev https://www.merriam-webster.com/dictionary/Kyiv
NAY-toh https://www.merriam-webster.com/dictionary/NATO
[d]mah-zshih-no https://www.merriam-webster.com/dictionary/Maginot%20Line
sharl duh gaul https://forvo.com/search/Charles%20de%20Gaulle/
[e]GWODDA-loop https://www.merriam-webster.com/dictionary/Guadeloupe
shaw https://www.merriam-webster.com/dictionary/shah
Iran = ear-RON
eye-uh-TOLE-uh https://forvo.com/search/Ayatollah/
roo-hoh-LUH hhhoh-may-NEE https://forvo.com/search/Sayyid%20Ruhollah%20Musavi%20Khomeini%20khomeini/
moh-HAWM-mid MOH-SAH-deck / MOSA-deck https://forvo.com/search/Mohammad%20Mosaddegh/
[f]Iraq = ear-ROCK
[g]grawnd arr-MAY https://forvo.com/search/Grande%20Arm%C3%A9e/
[h]kwuh-RAZMEE-in https://youtu.be/92-440OR2ik?si=zoJn2fSHMF55mIPS&t=71