What do you believe is the biggest missed opportunity in history?

[EmperorofPaldea]

I’d say - in 1939, the British and French not using the opportunity to conduct a proper offensive into Germany while they were distracted with Poland. Could have potentially nipped the Second World War in the bud and saved the lives of millions of people.

 

[ninazrdl]

It's not that easy. The British and French were trying to let the Soviets fight the Nazis at the time, ideally that should save millions of British/French life while weaken the two villains. If you destroy Germany only, it would be the Soviets vs. the rest of the world. Probably something like the Cold War, but not exactly cold. Please remember that Stalin isn't any better than Hitler as a leader, and he helped several other villains such as Pol Pot and Mao to come in power and kill more people.
Things must be stopped earlier...The Russians should have stopped the communist revolution, and the world should have helped, that really can save millions of people. However that must be very difficult.

I see the biggest missed opportunity being Japan. They seemed to have a bright future in the Meiji/Taisho era. People were learning foreign languages and new science, and they enjoyed new culture. They even had Taisho Democracy! The rich liked western culture and even had westernized hobbies such as sport plane racing at the time. The females were getting more education. The education system was using more foreign languages than the badly-translated Japanese versions they are using nowadays... and then! Somehow just after a few years they ended up Kamikaze-ing! Treating their own citizens like trash!