Fifteen volunteers spent 40 days inside a French cave without clocks, sunlight or phones and emerged believing only 30 days had passed

On March 14, 2021, fifteen volunteers, seven women and eight men aged between 27 and 50, entered the Lombrives cave in the French Pyrenees to begin a 40-day experiment with no clocks, no phones, no natural light and no contact with the outside world. Known as Deep Time, the project was led by French Swiss explorer Christian Clot through his nonprofit research group, the Human Adaptation Institute, and was designed to study how the human brain tracks time and how a group adapts psychologically and physiologically to prolonged isolation.

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