The Wikipedia page for Jules Vernes novel Around the World in Eighty Days comments that Verne is often characterised as a futurist or science fiction author, but there is not a glimmer of science-fiction in this, his most popular work.
Well, there is no generally agreed-upon definition of science fiction (see this list of proposed definitions; my own view is that its a family-resemblance concept for which no precise definition should be expected). Some definitions do require that the storys milieu be different from our own as the result of scientific or technological advances and by that standard Around the World indeed does not count as science fiction. But at least one popular definition or family of definitions focuses merely on the idea of a story that depends crucially on some point of science without necessarily involving extrapolation to some alternative milieu. Given that the plot of Around the World turns on the fact that one gains or loses a day when crossing the international date line, the novel thus does count as science fiction by some definitions (geography being, yknow, a science), so the not a glimmer line is something of an exaggeration perhaps yet another example (see here and here) of the bizarre resistance on the part of some Verne fans to seeing Verne characterised as a science fiction writer. At any rate, those who make these pronouncements seem oddly incurious about what the proper contours of the concept of science fiction might be.
I would add that Vernes Captain Hatteras, generally not considered sf, has even greater claim than Around the World to the category, since it portrays a successful expedition to the North Pole at a time when this had not yet happened, and speculates (inaccurately, but not impossibly) as to what would be found there thereby turning (unlike Around the World) not just on a point of science but on an extrapolated future development of a science (viz. geography); and similar remarks apply to Five Weeks in a Balloon and Measuring a Meridian. Those who deny it the title of sf are implicitly assuming, I suspect, that the only relevant extrapolations of science are those that involve new technology.