Throughout historic legends, there was stories of the dragons, such as Jormungandr for Norse mythology and the Leviathan from the Bible, that clearly depict humans coexisting with animals that very much resemble dinosaurs. In the case of Jormungandr and the Leviathan, the seemingly disparate legends appear to describe the same legendary sea animal that resembles an aquatic dinosaur, according to the very interesting book “Norse Mythology Rooted in Ancient Mesopotamia”. The word dinosaur didn’t exist until the 1800s. Before that time, dinosaur bones were still being found, but that most etymological common name for such animals was associated with legendary stories of dragons. The word “dragon” is assumed to have been a catch all name for all animals found alive or dead (ex. fossilized) that resembled dinosaurs. But this leads to the obvious, did ancient humans go-exist with “dragons” as the legends state in order for them to associate physical characteristics currently attributed to dinosaurs to dragons? I personally suspect that some dinosaurs did indeed survive mass extinctions and co-existed with humans in the ancient past before they too went extinct.
There is evidence that some exist today in remote locations, like in central African in the middle of its massive jungles as some recent eye-witness reports suggest (documented by the History Channel and televised).
(image owner: https://en.wikipedia.org/wiki/Dragon#/media/File:Martorell_-_Sant_Jordi.jpg)
The following video by “Restoring Genesis Film” documents well the subject of dragons.