In 1972, a French scientist, Michel Siffre, locked himself in a pitch-black cave 440 feet underground for 180 days.
No clock.
No human contact.
Next up, the adventurous Beatriz Flamini from Madrid descended 230 feet underground in November 2021, embarking on a wild expedition dubbed “Timecave.”
Michel Siffre wanted to uncover the secrets of the human mind—and what he found was literally TIME-BENDING:
Michel Siffre was a geologist and researcher obsessed with understanding human biology in extreme conditions.
He believed the key to unlocking the human mind lay in its relationship with time.
To test this, he devised a radical experiment.
Siffre volunteered to live completely isolated in a cave.
No clocks
No sunlight
No way to track time
He wanted to find out:
• How the brain reacts to total isolation
• What happens when you’re cut off from natural cycles
The world thought he was insane.
In 1972, Siffre descended 440 feet underground into a cave in Texas.
No contact with the outside world
No sun to guide his days
Just him, a sleeping bag, and tools for survival
The darkness was absolute.
The silence, deafening.
At first, Siffre tried to maintain a routine.
He followed hunger and fatigue to decide when to eat and sleep.
But without sunlight or clocks…
His sense of time began to distort.
Hours felt like minutes
Days blurred together
Siffre’s mental state deteriorated quickly:
• He hallucinated shadows and voices
• He became paranoid—convinced someone else was in the cave
• His thoughts spiralled into chaos
The isolation was breaking his mind.
He had a team above ground:
His team above ground was watching everything.
They recorded his activity to compare it to real time.
The results?
Siffre was completely disconnected from reality.
By Month 2, he believed 24 hours had passed when it had been nearly 48.
His internal clock had slowed drastically.
His body created a new rhythm:
• 36 hours awake
• 12 hours asleep
This shocked scientists.
Humans evolved to follow the 24-hour circadian rhythm set by sunlight.
But without sunlight, Siffre’s body invented its own clock—independent of the sun.
It was proof that the human brain has a built-in time system.
But there was a darker discovery.
As weeks turned into months, his mental state worsened:
• He forgot words mid-sentence
• He struggled to remember basic facts
• His emotions swung wildly between joy and despair
Isolation was rewriting his brain.
Siffre later described the experience as:
“A slow slide into madness.”
He talked to insects for company
He found comfort in his own voice
But silence always returned, crushing and relentless
After 180 days, Siffre was pulled out of the cave.
To him, only 151 days had passed.
He was stunned to learn how much time he’d lost.
Without external cues, his brain lost its grip on time.
Siffre’s experiment revealed:
• Time isn’t just external—it’s something the mind actively creates
• Isolation and sensory deprivation warp this ability, causing disorientation
His findings transformed understanding of time perception.
They led to breakthroughs in:
• Circadian rhythm research
• Space exploration (astronaut isolation)
• Mental health in solitary confinement
But the cost was high.
Siffre didn’t emerge unscathed:
• He suffered permanent memory loss
• His mental health took years to recover
• He described the cave as “an endless night” that haunted him for decades
He paid a steep price for his discoveries.
Yet despite the trauma, Siffre continued his research.
He later isolated himself in other caves to replicate his findings.
His work laid the foundation for modern sleep science and time psychology.
But the questions he raised remain:
What is time, really?
Is it a construct of the external world—
Or something created by the mind?
Siffre’s experiments showed that time is both.
And that the mind holds the ultimate power to shape it.
“The mind is a universe of its own.” – Michel Siffre
Siffre’s wrote that he’s legacy:
Of both the resilience and fragility of the human brain.
And how isolation can reveal the depths of our inner world.
Or there could be so many other answers:
Isolation was rewriting his brain, but it sounds like his body was no longer able to properly regulate its chemicals, probably due to lack of sunlight, and it was causing memory loss and behavioural changes.
It’s perfectly obvious that time does exist. We’ve got the sun by day, the moon and stars at night; morning and evening. The Earth goes around the sun, and we only get to do that so many times.
We’ve got four seasons every year. If you think of it, we all kind of all live within one massive clock.
This scientist may have just blinded himself to it for a while, but he was still just as subject to its effects.
He still got older at the same rate as everyone else but much less predictably.
An instrument being played out of time with the rest of the orchestra still eventually reaches the end of the piece and the end of the concert.
Then we have Beatriz Flamini…
Spanish Woman, 50, Emerges from Cave After 500 Days Alone Underground: ‘I Didn’t Want to Come Out’ she said.
Beatriz Flamini of Madrid began living 230 feet below ground in November 2021
Flamini was 48 years old when she first entered the cave in Granada, according to the BBC and Reuters.
During the experiment, Flamini was monitored by psychologists, researchers and speleologists, who study caves, though they never made contact with her, per the reports.
Flamini said she lost track of time after about two months, according to the AP and BBC. However, the mountaineer thought she had only been underground for about 160 or 170 days.
Flamini said she never considered pressing the panic button she was given, according to Reuters.
She even pressed on through a fly invasion, which left her covered in bugs.
The extreme athlete also experienced “auditory hallucinations” while in the cave, per the BBC’s report.
She needed assistance standing up while speaking with reporters because of balance issues.
Still, Flamini was thrilled by the experience, which she called “excellent” and “unbeatable,” according to the AP and BBC.
“You have to remain conscious of your feelings,” Flamini said, per Reuters’ report.
“If you’re afraid, that’s something natural but never let panic in or you get paralyzed.”
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