Warning: Spoilers ahead for Silo season 2, episode 10!Siloseason 2 finally explains how the world was destroyed, one of the biggest mysteries lingering throughout the Apple TV+ show. While the state of the outside world has been made abundantly clear, there have still been theories floating around about how the world became uninhabitable, killing anyone who is exposed to the toxic atmosphere without proper protection. Juliette, of course, becomes the firstSilocharacterto successfully survive the outside world.

Siloseason 1’s endingrevealed a better look at the destruction of the world’s surface as Juliette left her home before trekking over to Silo 17. It’s there that she learns more about the existence of other silo structures, as well as the threats the citizens inside the structures face. There’s still a lot of story to tell, butSiloseason 2’s ending flashbackreveals more details about the events that go on to cause the post-apocalyptic world on display in the show’s present timeline.

Bernard sending Juliette outside in Silo

Silo Season 2’s Flashback Confirms Theory That “Dirty Bombs” Destroyed The World

The Apple TV+ Show Reveals Conflict Between Iran & The United States

After showing what happens to Juliette inSiloseason 2, the finale flips to a surprising flashback, depicting a time before the world was destroyed. In it, a young Georgia congressman meets a woman in a Washington D.C. bar for what he thinks is a date. Before he enters the bar,security scans him for radiation, revealing that a dangerous incident occurred in the US prior toSilo’s flashback scene. When the congressman meets with his supposed date, Helen, they begin discussing where they were when “it happened,” with the “it” being a “dirty bomb” orchestrated by Iran.

The flashback characters inSiloseason 2’s ending don’t go into specifics about the Iranian bomb, but they do mention D.C. as the site of the incident.Helen then confirms that she works forThe Washington Postand wants to meet the congressman to get answers from fellow US citizensregarding the existence and use of dirty bombs. Helen questions whether there are plans “to strike back against Iran and whether or not there really was a radiological weapon attack on the United States.”

Rebecca Fergusson as Juliette in Silo

Siloseason 2’s flashback implies that the international conflict worsened, justifying Helen’s worry on behalf of citizens.

Even at this point in theSilotimeline, there were questions about the conflict and the legitimacy of a “dirty bomb.” Rather than one event that immediately impacted the entire country,Siloseason 2’s flashback implies that the international conflict worsened, justifying Helen’s worry on behalf of citizens. Based on the condition of theoutside world inSilo, it sure seems like the D.C. incident was just the beginning of a bigger war involving radiological warfare, making the country, and eventually the world, uninhabitable, at least presumably.

Juliette (Rebecca Ferguson) walking through a dark tunnel filled with corpses in Silo Season 2 Episode 1

What Happened To The Outside World Has Been One Of Silo’s Biggest Mysteries

Specific Details About The Apocalypse Hadn’t Been Discussed In The Show

Silotakes place in a dystopian future; that aspect is instantly made clear in the Apple TV+ series. Still, the specific event that turned the country into an apocalyptic wasteland, causing people to survive in silos, has been a lingering mystery. BySiloseason 1’s ending, it’s confirmed that the atmosphere is toxic and will kill anyone unless wearing specialized suits andSilo 18’s special heat tape. While some silo inhabitants have questioned the validity surrounding the state of the outside world, Juliette confirms the truth when she returns to Silo 18 in season 2’s finale.

How Long Ago The Rebellion Happened In Silo 17

Many story developments in Silo season 2’s episode 9 finally reveal the truth about the mysterious timeline of Silo 17’s rebellion and Solo’s past.

Unlike nuclear bombs, which had been another popular theory linked to what destroyed the world inSilo, the use of dirty bombs disperses radioactive material over a large area, contaminating the atmosphere for long periods. The show has implied thatSilo 18 has sheltered people from the outside world for over 300 years, with season 2 confirming the existence of at least 50 different silos. With the conditions still inhabitable on the surface for centuries, the existence of underground shelters can now be seen from a new perspective.

Silo TV Poster

How The World Was Destroyed In The Silo Books

The Silo Book Series Takes A Prequel Approach With “Shift”

Warning: Spoilers for Hugh Howey’s “Shift” arc, which covers novellas 6-8 in the series!Other than"cleaning" inSilo, any discussions about the outside world are treated as somewhat taboo in the show. Possession of relics from the “before times” is a punishable offense, and information centered on the country’s history before the radiological event is kept locked in silo vaults. It’s unclear whatSiloseasons 3 and 4will reveal about the world’s history and destruction. However, Hugh Howey’s books, on which the show is based, provide more insight into what happens to Earth’s surface. ThoughSilohas made changes to the books, viewers can likely expect some aspects to be revealed in future seasons.

2011

2013

Dust

In Hugh Howey’s “Shift” arc, the origins of the silo come into focus, revealing that the underground shelters are built in case of nuclear-related emergencies. Soon after,nuclear bombs wipe out Earth’s surface in what was actually connected to World Order Operation Fifty (W.O.O.L.). After dangerous nanotechnology threatened humanity after becoming weaponized, Operation Fifty was put into place to cause a nuclear apocalypse meant to destroy the population aside from those in the silo shelters. The plan was to allow the remaining “good” nanobots to clean the surface until it was safe for the silo citizens to go back to the surface.

Silohas two more seasons to fully share their version of the books' complete story, seeing as the Apple TV+ adaptation is set to conclude with its fourth season. A portion of the remaining story will also bring back Helen and the congressman based onSiloseason 3’s plans to bring back Jessica Henwick and Ashley Zukermanas series regulars.Silomay not fully follow the books when it comes to Operation Fifty, but there are still plenty of aspects from before the major “incident” worth diving into.