By Ford James Published Nov 3, 2026, 11:00 PM EST Opinion Mount Chiliad spawned thousands of theories
Image: Rockstar Games Add Polygon.com on Google Add as Preferred Source Follow on Google Discover Sign in to your Polygon.com account Summary Generate a summary of this story Like Like follow Follow followed Followed Thread Log in Here is a fact-based summary of the story contents: Try something different: Show me the facts Explain it like I’m 5 Give me a lighthearted recap In Grand Theft Auto 5 , one landmark was visible practically no matter where you were in San Andreas: Mount Chiliad. "Claimed by the Spanish in 1769, Mount Chiliad is the highest peak in San Andreas, sitting at a height of 2,744 meters," reads a sign at the nearby Silent Probe Mountain art installation. "Taken under Mexican control in 1821, it was then, and remains in American hands since 1847."
It's more than just a mountain, though. Once the player has achieved 100% story completion, standing atop the mountain at 3 a.m. during cloudy weather reveals a UFO, hovering in the night sky. It's marked with an F.I.B. logo, aka the Federal Investigation Bureau, implying that it was created by the government. However, there's also reason to believe that the mysterious aircraft is a hoax, because it doesn't react to bullets, and raindrops nearby become pixelated.
The running theory is that it's a hologram, as opposed to the two other functional UFOs in the game, which are physical objects. They're located high in the sky above both Fort Zancudo and the Silent Probe Mountain respectively, they can both be collided with, and they emit electromagnetic pulses that cause the player's vehicle to shut down if they get too close. There's reason to believe they're both also government-controlled: the former visually looks somewhat similar to a real-life B-2 Spirit stealth bomber and, when viewed using third-party software, has two human pilots inside. The latter also has F.I.B. printed on the side, much like the UFO above Mt. Chiliad.
Players knew there was at least one secret at the top of the mountain, thanks to graffiti on the back of the observation deck that reads "come back when your story is complete." GTA Online revealed that the mountain is also home to a nuclear launch facility. But some players are convinced that Mt. Chiliad holds one final mystery that is still unsolved to this day.
Inside the tramway station near the summit, a mural depicts an abstract interpretation of the mountain itself. At the top is an eye, while the exterior of the mountain has lightning bolts emanating from it. Inside the mountain is a maze of perpendicular connecting lines. Each one connects to one of eight squares. Five of them are small, marked with an X inside. The three larger ones at the bottom of the picture show, from left to right, a UFO, a cracked egg, and a person wearing a jetpack.
Image: Rockstar Games via Polygon One week after GTA 5 was released, on Sept. 24, 2013, fans created the Chiliad Mystery subreddit . For the last 13 years, users there have been dedicated to uncovering the secrets believed to be held within. The community worked out that the X's correspond to petroglyphs hidden around the mountain, each of which depicts a weather status required for the Mt. Chiliad UFO to appear. There's also a theory that each X also represents the roman numeral for 10, and since there are five of them, it's representative of the 50 collectible spaceship (aka UFO) parts scattered acros…