Quote from an article at Space.com:
925 feet - maybe they could give Herbert a ride to the abbyss. He could save so on the sled developmentA robotic yellow submarine will journey this week to the world's deepest sinkhole, which already has taken the life of one diver who sought to reach its bottom and discover the life that might exist there.
Others have tried to reach the end of this seemingly bottomless pit in the Mexican state of Tamaulipas, known to be at least 925 feet deep, but no one has ever succeeded.
The self-automated "DEPTHX" (Deep Phreatic Thermal Explorer) will search the depths of the El Zacaton cenote, or geothermal sinkhole, for life and also study its dimensions and look for the vents that feed it.
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