It's common to describe getting a good night's rest by saying we've had a really deep sleep. But in reality, actual deep sleep is just a portion of the 7 to 9 hours sleep that's recommended for ...
When Hans Hartman, a civil engineer, attempted to film the ocean depths in 1917, he pioneered what would become the first deep-sea ROV, or remotely operated vehicle. During an era of silent movies ...
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