Sousaki Volcano: The One You Didn’t Know Exists

Εσείς το ξέρατε ότι στον νομό Αττικής έχουμε ηφαίστειο; Λίγο έξω από την Αθήνα;! Στους πρόποδες των Γερανείων, στην περιοχή των Αγίων Θεοδώρων, πάνω από την Εθνική Οδό (με κατεύθυνση το ρεύμα προς Κόρινθο)! Αν το «γκουγλάρετε» θα βρείτε αρκετές αναρτήσεις, από τις οποίες ξεχώρισα ένα άρθρο της Μηχανής του Χρόνου με βίντεο και εντυπωσιακές λήψεις από δρόνο.

Did you know there’s a volcano just outside Athens? Not the dramatic, postcard kind; with no white houses around it, no caldera sunsets, no crowds chasing the perfect photo. This one is quieter, stranger, almost forgotten.

About 37.3 miles (65 km) from Athens, near Agioi Theodoroi in Corinthia, sits Sousaki—an unassuming landscape that hides one of Greece’s least-known volcanic sites. Hundreds of Greeks and tourists drive past it on the Athens–Corinth highway each season, without ever realizing what’s breathing in the slopes above!

A volcano that doesn’t look like one

Sousaki doesn’t fit the image most of us have in mind when we hear the word volcano. There’s no dramatic cone and no crater waiting to be admired from above. Instead, the land feels fractured, like something underneath it once stirred and never fully settled.

The area forms the northernmost edge of the South Aegean volcanic arc, the same chain that includes the volcanos of Methana, Aegina, Poros, Milos, Nisyros, and Santorini. All of them were shaped by the slow, relentless collision of the African and Eurasian tectonic plates—a process that quietly rewrote the geography of Greece thousands of years ago.

A mountain with… hiccups

What makes Sousaki distinct isn’t what you see first, but what you sense. Or maybe I should just be honest here and say smell—it’s what you smell… Sulfur; sharp, unmistakable, thick and intrusive, like something ancient pushing its way to the surface.

The ground itself seems restless. Dozens of small openings (ports)—scattered across the rocky terrain and inside the gorge—release warm gases into the air. Carbon dioxide, methane, hydrogen sulfide. Invisible, but very much present. The smallest birds and rodents that foolishly hang around these burrows faint and die from the poisonous gases, and their mummified remains can make the hike just a tad lurid!

A quiet past, an active presence

The last known volcanic activity here dates back about 2.7 million years. By most definitions, Sousaki is long dormant. And yet, standing there, it doesn’t feel inactive. The gases continue to escape. The rocks continue to erode and reshape under their influence. The landscape continues to evolve in slow, almost imperceptible ways. There are even old mining tunnels scattered in the area—remnants of sulfur extraction that once took advantage of what the earth was offering.

So close—and almost invisible

What’s perhaps most surprising is how close all of this is to everyday life. Thousands of cars pass nearby every day. People commute, travel, head off on weekend getaways—completely unaware that just a few minutes away lies a place that feels almost otherworldly. And even those who catch a faint sulfur smell through the car window might never guess its source, most confusedly assuming it emanates from the Corinth Refinery facilities a few miles away.

From Sulfur to Serenity: Where to Stay in the Area

Things People Actually Said Near Volcanoes

 “Most volcanologists die in bed.” ― Volcanologist Maurice Krafft

“What time does the volcano erupt?” ― Tourist on Mt. Etna in 2000

“No one told us we needed a gas mask” ― Tourist visiting remote Ambrym volcano in South West Pacific

“We’ll just look at you. If you look scared then we’ll panic.” ― Discovery Channel crew comments to Volcanologist John Seach while filming at Yasur Volcano in 2000

“Do we need to bring a sleeping bag, or will the volcano keep us warm at night?” ― Documentary producer at Mt. Etna in 2000

“We will be bringing the best, insured cameraman.” ― Documentary producer discussing the close-up filming of lava in 2003

Classic Volcano Quotes – John Seach