Update: Seems the linked video has been censored.
Many cultures have narratives concerning the existence of giant humans during the past, and the web channel Mystery History, has uploaded a short video on the topic.
The presence of enormous quarried stone megaliths as well as megalithic structures and buildings constructed for larger sized “humans” is, to this author, blindingly obvious. What jars the sensibilities of settled science is the conflict of this evidence with settled theory and dogma, especially the belief in biological evolution as championed by Richard Dawkins, for example. Evolution is actually slow-motion Creationism, and retains its role of preferred explanation in settled science because it is compatible with the Western Judeo-Christian cultural narrative.
The author of the video did make one interesting point in that he proposed a past global catastrophe that changed the environment so much so that the biological species adapted to the new conditions of greater gravity so that giant life forms co no longer function, or live, and adapted by becoming smaller. No new species, or breeds, appeared, just the old ones changing to the new environmental conditions.
One fact not understood is the geological belief that life forms are continuously preserved in sedimentary rocks by accidental burial. This idea is nonsense.
If we assume the Earth was originally a highly weathered rain forest world with abundant life forms, having a gently undulating topography not dissimilar to Venus, and with epicontinental shallow seas, a vegetation world like the Star Wars Yoda’s home of Dagobah, then life forms will not accumulate but would be continuously recycled in the biosphere.
The Cambrian Explosion inferred from the abundance of fossils in sediments is nothing other than the extinct buried remnants of various life forms extant before some global catastrophe killed them and caused an environmental change which the survivors then had to adapt to. No earlier fossils existed because fossilisation of life forms is a strictly catastrophic event in which the life force has to be almost instantly stopped before putrefaction and decay occurs. Which means that the fossilisation event also had to terminate the various bacteria and other microscopic life forms that macro species are formed from. The only known physical force having the capability of instantly killing life is Electromagnetics via the plasma medium. Electrocution in other words.
It is likely that life has always existed, in a universe with no start nor end, continuously adapting to changed conditions and environments, with no new species formed, but new breeds appearing as adaptation.
But as long as the religiously devout still cling to their core belief or faith in Creation, whether 6000 or 4,500,000,000 years ago, from which earth formed from an accretionary gravitational process, and life appeared spontaneously 600 millions years ago as the Cambrian Explosion, then settled science will remain totally settled in self imposed ignorance.