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The two Great Unknowns, the two Illustrious Conjecturabilities! They are the best known unknown persons that have ever drawn breath upon the planet.

Mark Twain (2013). “Delphi Complete Works of Mark Twain (Illustrated)”, p.4064, Delphi Classics
The two Great Unknowns, the two Illustrious Conjecturabilities! They are the best known unknown persons that have ever drawn breath upon the planet.