Neurons were first extensively illustrated by Cajal in ~1890. When he looked at a tissue of the brain, here’s what he painted:
At that point in time, we didn’t know that galaxies other than the Milky Way existed. We didn’t even know that atoms consisted of electrons and protons.
Fast forward to today. We now know that our galaxy is simply one of the 100 billion galaxies out there. We have not only discovered protons but now know that they aren’t even fundamental particles, quarks are. We’ve imaged black holes, detected gravitational waves. We have an accurate account of the universe’s origin starting from the very first moments. In short, we’ve pretty much nailed our understanding of the physical universe since the time Cajal first looked at the brain. ...