The ten times the world was almost destroyed in Naruto were a series of events which almost tossed the world into chaos. Despair and war exist in the Realm of Fire, yet somehow the biggest players always wish to destroy mankind.
It doesn't matter if it's for their simple enjoyment or wrath, the earth has almost shattered multiple times in the span of a few decades. Calamity and despair peek around the corner and wait in the eye of the storm.
If it wasn't for Naruto and his allies, no one would be alive to tell the tale of his heroics. However, the villains and primordial gods think otherwise.
Shukaku, Nine-Tails, and more are responsible for almost destroying Naruto's world
1) Nine-Tails' attack
This attack occurred sixteen years ago in the Village Hidden in the Leaves, the one event that defined Naruto's life. It seemed like the end of the world as the Nine-Tailed Fox ravaged the land. It killed several villagers, including the Hokage, until he and his wife finally sealed it inside Naruto.
The Nine-Tails is a demon of mass destruction who wishes to kill humanity. It was unsealed by Obito Uchiha in an effort to destroy the Hidden Leaf for the crimes they committed in the past.
2) Wrath of Shukaku
Shukaku distrusts most humans, so when it saw an opportunity to destroy the Village Hidden in the Sand, it attacked. The world was almost destroyed by the simple fact that no one bothered to seal him until it was too late. He ravaged the Sand until the Kazekage stopped him.
Shukaku itself is an arrogant beast that loathes humanity. It told Gaara that if he dared to fall asleep, it would take control of Gaara's body and wreck havoc. As a result, Gaara developed insomnia, which he still suffers from to this day.
3) Pain's Attack
Pain attacked Hidden Leaf in the wake of Jiraiya's murder. He and his Six Paths of Pain planned to destroy the village so that peace could be maintained. He explained to Naruto that humans are spoiled beyond belief, and that they don't understand what others go through if they don't experience it themselves.
He would therefore drag them into the jaws of torment so they could come out compassionate. He used the Six Paths of Pain to destroy the Hidden Leaf. If Naruto hadn't defeated him, the world would have been at his mercy.
4) Akatsuki
The Akatsuki is a criminal organization bent on sacrificing the Jinchuriki in order to awaken the Ten-Tails. They attack innocent civilians and other important figures if it suits their cause. They will be a major threat to the entire world if the Ten-Tails gets resurrected.
Even when their numbers shrank, they somehow managed to resurrect the Ten-Tails in the midst of the Fourth Shinobi World War. It murdered thousands of people and almost achieved Akatsuki's goal.
5) Orochimaru, the Immortal
Orochimaru is an insidious man who prefers the company of shadows. He frequently kidnaps children and experiments on them on a daily basis. Some of these children continue to grow up to become mass murderers and spread the ideology of Orochimaru.
He is a constant threat to the world, as he forces children to endure his Curse Mark. If he dies, he can be resurrected if the Mark is activated. He has also been known to steal the bodies of people he's kidnapped and wear them as if they're his own.
6) Kabuto, the Warmonger
Kabuto performed the Reanimation Jutsu on the corpses he found and brought them back to life. However, they were under his control and had no will of their own. He sent the army of the dead to attack all nations. He started the Fourth Shinobi World War.
He studied under Orochimaru and learned his insidious ways. His actions plummeted the world into another world war and killed thousands of people. If Itachi hadn't stopped him, he would have destroyed mankind.
7) God Tree
The God Tree devours the blood that spills from the aftermath of war and carnage. It's a tree planted by the Aliens as a form of dominion over all life forms. The goal they wrought is for the tree to absorb all the chakra from the world until the planet perishes.
It almost ended the world once by supplying Kaguya with the chakra it absorbed from the world. Kaguya herself merged with the tree in a show of absolute power and almost destroyed the pre-Shinobi world in the war with her sons.
8) Eye of the Moon
This plan was produced by Madara Uchiha in an attempt to create a false world of hope. The plan consisted of him hypnotizing the mankind until they fell into a deep slumber. Their dream would be whatever wonderful fantasy they had always envisioned, but ten times as beautiful.
This was Madara's plan for eternal peace. No more humans would be born, war would cease, and the slumbering victims would grow old and die. His plan was in the making for over a hundred years, and seemed too meticulous to work, but it did. However, he was stopped by Naruto and his descendant, Sasuke.
9) Kaguya
An alien from a strange realm, Kaguya is a force to be reckoned with. She possesses both the Sharingan and Rinnegan, as she is the mother of all chakra. Though her intentions are vague, her ideal is for the world to give her its chakra back, no matter the cost.
When she was unsealed in the Fourth Shinobi War, she tormented Team Seven until even they could barely stand it. She almost succeeded in plunging the world into a vast darkness, but Naruto and Sasuke sealed her away.
10) Ten-Tails
Ten-Tails is the combination of Kaguya and the God Tree in the form of chaos. It has several forms, though each is worse than the first. It's sole purpose is unclear, though destruction follows in its wake.
It almost ended the world once it was restored to full power by Madara and Obito. It ravaged the land and devoured the blood of thousands, but it still wasn't enough. Luckily, Naruto stopped it before the world was destroyed.