In April of this year, Spanish athlete Beatriz Flamini emerged into the light after a 500-day stay in a cave. Her descent underground is probably the longest undertaken by a long stretch. Flamini says she lost all sense of time on the 65th day. But can she really be sure it was the 65th day? By way of comparison, in 1962 France’s Michel Siffre surfaced from the Scarasson chasm in Italy after spending what he thought was 33 days there. In fact, he spent 58 days underground.
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Source: Phys.org