20 Historical Events That, Had They Happened, Would Have Changed Everything

In 1962, the world came much closer to nuclear war than most people realized at the time. A Soviet submarine, cut off from all communication, nearly launched a nuclear torpedo after being targeted by U.S. forces. That it did not happen is largely thanks to one officer, Vasili Arkhipov, who refused to give his approval—an almost imperceptible gesture that likely averted a catastrophe.

The plot to assassinate Adolf Hitler in July 1944 nearly succeeded. The bomb exploded, but a slight shift in the position of the briefcase shielded him from the full force of the blast. Just a few more centimeters in another direction, and the power of Nazi Germany might have collapsed from within.

As Apollo 11 descended toward the Moon, alarms went off and the fuel level was dangerously low. Neil Armstrong had to manually maneuver the module away from a rocky landing site, and he landed with only a few seconds’ worth of fuel left. A different outcome could have turned this triumph into a tragedy watched by the entire world.

The Allied landings in Normandy depended largely on a brief lull in the terrible weather. If the operation had been delayed by even a day or two, the German defenses might have been better prepared. This brief lull helped determine the success of one of the most important operations of World War II.

A Soviet early-warning system once falsely reported the arrival of American missiles. Officer Stanislav Petrov chose not to report the incident as an attack, suspecting a malfunction. Had he followed protocol, the situation could have escalated immediately and irreversibly.

The failure of the 1961 invasion of Cuba was due to limited air support, which was ultimately scaled back. Without it, the operation quickly collapsed. A slightly different decision could have completely transformed relations between the United States and Cuba—as well as the tensions of the Cold War.

Before becoming queen, Elizabeth I faced imprisonment and serious threats to her life. A different political turn of events or a single decisive order could have brought her story to a premature end. England’s religious and political evolution would then have taken a turn that would have been difficult to fully grasp.

The Challenger shuttle was launched despite concerns about the proper functioning of the O-rings in cold weather. Engineers had sounded the alarm, but the decision stood. A delay of just one day might have prevented one of the most devastating disasters in NASA’s history.

A German battle plan, detailing troop movements, was accidentally lost and later recovered by Allied forces. This intelligence allowed the Allies to prepare for the impending attack. Had it remained lost, the outcome of decisive battles might have been radically different.

Before his assassination, JFK had already narrowly escaped several dangers, including health problems and previous threats. Any one of these events could have upended the political landscape even before the 1960s began. History often overlooks just how events could have taken a different turn much earlier.

During an assassination attempt in 1835, the two pistols aimed at President Andrew Jackson misfired. This was an almost improbable mechanical failure that occurred twice in a row. If either of the weapons had fired, the presidency—and American politics—would have immediately taken a different turn.

The RMS Olympic, which was nearly identical to the Titanic, was involved in several serious incidents but narrowly escaped disaster. These close calls demonstrated just how easily the Titanic could have met the same fate. It wasn’t just bad luck—it was a situation that was bound to happen.

When the first nuclear test was conducted in 1945, no one really knew if it would work or what the exact effects would be. Some scientists even feared it might set the atmosphere on fire, as unlikely as that might seem. The success of that test upended the global balance of power in an instant.

In 1961, American and Soviet tanks faced off at Checkpoint Charlie in a tense standoff. For a brief moment, it seemed as though a single shot would be enough to trigger an all-out conflict. Both sides eventually retreated, but the situation was extremely precarious.

Vladimir Lenin survived an assassination attempt that left him seriously wounded. His survival allowed him to continue shaping the early days of the Soviet state. A different outcome could have completely altered the course of the Russian Revolution.

England’s defense against the Spanish Armada was not only military; it was also meteorological. Violent storms scattered and damaged the Spanish fleet at decisive moments. Without those weather conditions, the balance of power in Europe might have shifted.

In 2013, an asteroid passed closer to Earth than many satellites. It did not collide with Earth, but this close encounter served as a reminder of just how narrow the margin of safety can sometimes be. Such events do not make history, but they could very well do so.

Roosevelt was shot in 1912, but he continued his speech even as the bullet remained lodged in his chest. The thick stack of papers he had in his pocket slowed the bullet enough to save his life. If his speech had been shorter, the outcome might have been very different.

In 1814, British forces invaded Washington, D.C., and set fire to key government buildings, including the White House. President James Madison had already fled, and the situation was far more precarious than is generally realized. Had the British continued their advance or succeeded in capturing key leaders, the young United States might have faced a severe political collapse at a critical moment.

A training simulation was accidentally uploaded to an operational system, giving the impression that a large-scale nuclear attack was underway. For a brief moment, actual response protocols began to be triggered. The error was detected in time—but only just.