A team of Czech cave explorers has uncovered the world’s largest underground thermal lake, hidden deep beneath the surface of southern Albania.
The stunning body of water, stretching 138.3 meters in length and 42 meters in width, holds an estimated 8,335 cubic meters of mineral-rich thermal water.
The team had to descend 127 meters underground to reach the lake, making it one of the most extraordinary geological finds in recent years.
The discovery was the result of years of exploration led by Czech speleologist Marek Audy, who first suspected the existence of a hidden thermal cave system in Albania’s Vromoner region on the Greek border.
A descent into the unknown
The team had to descend 127 meters underground to reach the lake, making it one of the most extraordinary geological finds in recent years.
The discovery was the result of years of exploration led by Czech speleologist Marek Audy, who first suspected the existence of a hidden thermal cave system in Albania’s Vromoner region on the Greek border.
Guided by his intuition based on experience with similar geological formations in the Guadalupe Mountains of New Mexico, during a family trip Audy and his wife explored a cave known as Sulfur Cave, accessible from the Sarandaporo River.
“We weren’t the first people inside, but I had a strong feeling this cave was unique,” Audy recalled. Though he had promised his wife a warm thermal spring experience, the water temperature was only 26°C. Despite the conditions, Audy’s curiosity was piqued.
“With scorpions, spiders, heat, and an overwhelming stench, I wouldn’t exactly call it a romantic cave,” Audy said. “But I was already reaching for my notebook.”
Albania, long isolated during the communist era under dictator Enver Hoxha, has remained largely unexplored, leaving many of its natural wonders undiscovered. However, at the end of 2024, the team spotted something remarkable—drone footage revealed a plume of steam rising from an uncharted location.
Following the lead, the team discovered the vast underground cavern they would later name Atmos Cave, the largest known underground thermal lake on Earth.
Audy later told National Geographic: "When we first got into that cave and saw the lake, we were amazed. It was like entering another world."
The discovery has now been hailed by experts as a scientific milestone.
“We weren’t the first people inside, but I had a strong feeling this cave was unique,” Audy recalled. Though he had promised his wife a warm thermal spring experience, the water temperature was only 26°C. Despite the conditions, Audy’s curiosity was piqued.
“With scorpions, spiders, heat, and an overwhelming stench, I wouldn’t exactly call it a romantic cave,” Audy said. “But I was already reaching for my notebook.”
Albania’s hidden geological treasures
Albania, long isolated during the communist era under dictator Enver Hoxha, has remained largely unexplored, leaving many of its natural wonders undiscovered. However, at the end of 2024, the team spotted something remarkable—drone footage revealed a plume of steam rising from an uncharted location.
Following the lead, the team discovered the vast underground cavern they would later name Atmos Cave, the largest known underground thermal lake on Earth.
Audy later told National Geographic: "When we first got into that cave and saw the lake, we were amazed. It was like entering another world."
The discovery has now been hailed by experts as a scientific milestone.
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