Consider yourself lucky: in your lifetime you've probably lived through a few disasters that almost wiped out life on earth, even if you didn't realize it at the time.
Here are 10 times humans, as a species, almost bit the dust:
1. The Spanish Flu
As World War 1 was drawing to a close, a pair of deadly H1N1 pandemics began spreading around the world. The large number of people moving from place to place helped the disease spread, until it was recorded everywhere from remote islands in the Pacific Ocean to the Arctic Circle.
More then 500 million people around the globe caught the virus, and somewhere between 50 and 100 million died from it - that means 3-6% of the planet's population were wiped out in only 2 years. Life expectancy in the U.S. alone dropped by 12 years during the flu.
2. Stanislav Petrov's Close Call
A Soviet officer name Stanislav Petrov was working at a command center for the government's early-warning nuclear defense system on September 26, 1983 when he saw an unusual alert. His computer said the U.S. had launched a nuclear missile at Russia.
Stanislav was convinced that it was a false alarm, and his doubt is the only thing that stopped the Soviets from launching a counterattack that could have torn the world apart. The false alarm was later blamed on sunlight reflecting off high-altitude clouds.
3. The Toba Eruption
70,000 years ago, a massive super volcano in Indonesia's Lake Toba erupted, spreading enough ash into the atmosphere to cool the entire planet for up to 10 years.
Some experts believe this disaster almost wiped human beings off the face of the earth. Research suggests as few as 3,000 people living in Africa may have survived the long volcanic winter. While these theories are inconclusive, they may explain why modern humans are all so closely related.
4. The Bonilla Comet
In 1883, an astronomer named José Bonilla saw more than 300 dark objects passing in front of the sun, and recorded the weird sighting with photographs. For decades no one could explain exactly what Bonilla had seen, but a few years ago scientists offered a disturbing answer to the mystery.
Researchers at Mexico's National Autonomous University believe the objects were fragments of a massive comet passing dangerously close to earth. The object could have weighed as much as a billion tonnes, enough to wipe out all life as we know it on earth, and it passed less than 800km away from our planet.
Think that's scary? Another near miss happened in 2012.
5. The Coronal Mass Ejection
Do you remember where you were on July 23, 2012? You should, because that was the day our world nearly ended. A massive burst of solar energy called a Coronal Mass Ejection (or CME) shot into space. If it had happened just six days earlier it could have destroyed humanity.
Solar flares themselves aren't dangerous, but the energy they create disrupts electricity. If the flare was pointing at earth, like it was just a week earlier, it would have created a massive global blackout and blocked nearly all forms of communication.
What's worse, humanity would have been stuck in the dark for up to 10 years. That was a close call, but NASA says the odds of another event like this hitting earth in the next decade or so is 12%. Good luck sleeping tonight!
6. The Justinian Plague
It's not as famous as some other deadly viruses, but the Justinian Plague changed human history. At least 13% of the earth's population, 25 million people, were killed over more than 200 years as the disease spread through the Eastern Roman Empire.
Modern genetic studies show the plague was a global event, traveling to the Mediterranean from China. The plague is named for Roman Emperor Justinian I, who luckily survived the disease.
7. The Shaanxi Earthquake
Modern earthquakes are nothing to sneeze at, but if anything close to the Shaanxi Earthquake of 1556 happened again we may not survive. The massive disaster killed more than 800,000 people, toppling buildings in cities over 500 miles apart.
In some counties, as much as 60% of people were killed. It remains the deadliest earthquake of all time, and just imagine how much worse it would be in today's densely populated countries.
8. War Games
In 1979, a computer at NORAD headquarters almost started World War 3, all because an office worker got a little careless. A computer alert warned staff at the defense center that 250 Soviety missiles were speeding towards America, then 2,200.
"I knew that if it were true, then within about half an hour I, and my loved ones, and Washington, and the majority of America would cease to exist," a national security adviser said about his reaction to the news.
Luckily, staff quickly realized this was a false alarm. So what had happened? An employee was running a simulation of an attack on his computer, not realizing that it was linked to the station's real alarm system, sending everyone into a panic.
9. The Black Death
The same bacteria responsible for the Justinian Plague, yersinia pestis, resurfaced in Europe 600 years later and wreaked havoc and wrack up an even bigger death toll. Estimates are rough, but as many as 200 million people may have died from the disease.
While rats were blamed for spreading the disease for hundreds of years, modern researchers say rat fleas were actually responsible. Throughout the 14th century, the plague dropped the world population from 450 million to as low as 350 million.
It would take 300 years for humanity to recover, while the plague still exists to this day.
10. The Cuban Missile Crisis
How close did we really come to nuclear war during this 13 day crisis? Too close for comfort. It started when the Soviet Union moved missiles into Cuba, just 90 miles away from the Florida coast and close enough to strike Washington.
Tensions were high on both sides throughout the crisis, and a number of false alarms and itchy trigger fingers almost launched a full-blown war. The accidental death of an American pilot helped cool things down long enough for America and Russia to reach an agreement.
The crisis led to the introduction of the "red phone" between the two countries, a system to talk things over in case we were ever that close to starting a nuclear war again.
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