Meet the GTA 5 geologist uncovering the origins of Mount Chiliad with real-world science

In GTA 5, Mount Chiliad is a monster. Reaching higher than any other geographical feature in the San Andreas sprawl, the rocky range hugs the dusty drags of Blaine County at its base and kisses the clouds 800m above sea level at its peak. It is instantly recognisable, and yet shrouded in mystery, playing host to everything from supposed Bigfoot sightings to enduring Roswell-inspired conspiracy theories. 

After several years of debate, the latter 'Chiliad Mystery' was cracked in 2017 by an intrepid team of UFO-worshipping players, who made sense of a cryptic message board and the strict in-game parameters required to make contact with an alien race. Still, the mysticism surrounding the towering knife-edged monolith north of Los Santos persists today – so much so that junior geologist Prashanth Nair is now using science to uncover how the iconic mountain came to be in the first place. "The GTA community is really amazing," says Nair, otherwise known as ArcFX, "but while players spent years solving the Chiliad Mystery, I haven't seen anyone simply ask: how did this mountain form? That's where my videos come in."

Science shorts

In his first GTA-related YouTube short series, ArcFX spends 57 seconds hypothesizing on how Mount Chiliad was formed, suggesting that the entire top third of the San Andreas map – from the northern coast of the Alamo Sea all the way to the Paleto Bay peninsula – would have stood apart from the mainland, fully-submerged underwater, 100 million years ago. By combining in-game footage with easy-to-digest geological diagrams, ArcFX humorously posits the visible sedimentary layers on the mountain face are what has led him to this conclusion, and even reckons Chiliad is in its first stage of erosion. Admittedly, I do not know my sedimentary rocks from my tectonic shifts, but ArcFX nevertheless makes a compelling, easy to grasp argument to me as a lay person, and he assures me all of his claims are backed up by his university professor who holds a PhD in geology. 

"The main reason I make these videos is to combine my knowledge and love of geology with something fun," ArcFX continues. "When I play GTA 5, I tend to roam around the streets listening to music in the car, making observations on the world around me. Fieldwork is really important in geology, as you can imagine, but it's been tough to do so because of the pandemic. So, I just started looking around the wilderness of GTA 5 and applying the science to some of its landmarks in the hope that other people might find that interesting."

Besides Chiliad, ArcFX's shorts praise the authenticity of the rainwater drainage systems installed in and around the mountain area, but are critical of the "nonsensical" river placement up and down the sandbox. In the latter short, ArcFX is seen tracing each river by boat and bike in Story Mode – similar to how twister chasers track down tornadoes in real life, critiquing an environmental feature the vast majority of players, myself included, have undoubtedly otherwise overlooked. 

"I mean, first of all, GTA 5 is really realistic for the most part," says ArcFX. "But I would say, if you were to compare it with other games, there are some which have more realism when it comes to geological formation. For example, Skyrim, it's world is amazing in geology terms, even now over ten years on. In Far Cry 4, the map of Kyrat is just amazing too."

"These are video games, though. To be fair, GTA 5 is a video game, so it's probably not much of a surprise that some of it is copied and pasted. The developers, in my eyes, have basically copied and pasted the landforms they've seen in the real world. As my videos show, some of the geology then doesn't make sense as a result, but it's still really fun to explain how it might have been formed. In the Chiliad video, using the different areas around the mountain allows you to take a shot at explaining it. Even if it's not realistic, it's still pretty fun to try to explain it."

Don't look up 

At the time of writing, ArcFX has published seven shorts on the geology of GTA 5 – exploring the perceived geological formation of water arches, plunging canyons, and a polite factual rebuttal for doubters of his original Chiliad vid – and has plans to pull his thoughts together in one longer, more in-depth and informed video which he hopes will run for 10 or so minutes. Given their short, snappy, tongue-in-cheek and accessible appeal, ArcFX's videos are interesting and good fun, and I'm always a sucker for players applying their real-world expertise to elements of their favourite games. 

With GTA 5 now approaching its ninth birthday, I ask ArcFX what the future holds for Mount Chiliad, if long-term corrosion might be an issue, and, against the city's excess culture and with so many vehicles now touring the archipelago in 2022, is climate change a potentially major concern in modern day Los Santos?

"I mean, it's not just cars is it?" ArcFX says. "There's fighter jets and flying bikes and goodness knows what else on the roads and in the air. As for Chiliad itself, I think it'll keep corroding away, yes. Who knows, maybe it will be a flatland by the time GTA 6 comes out."

"As for me, shorts are great, they get you some views but they don't get you a core audience. I want to make longer videos that people can engage with and then maybe clip those up as shorts to use as promotion. My plan, longer-term, then, is to make longer videos for people to enjoy."