Continental drift or just the idea that the continents move. And it makes sense, looking at a map of the earth, you can clearly see that some landmasses look like they fit together like puzzle pieces. Combined with the fossil record with also supported this, it seems obvious to us now, the continents were once all one landmass. However, back then, the issue was Alfred Wegener, who came up with continental drift, didn’t have an adequate mechanism for how it worked. The question on everyone’s mind was, if the continents moved, HOW did they move? There wasn’t a good answer. It was suggested at one point that the continents maybe just plowed through the ocean crust. But that idea doesn’t work because the ocean crust is too rigid. So without any mechanism to get it to work, many geologists simply dismissed the idea. And to be fair to them, most of what Wegener claimed was indeed wrong.
Further advancements in geology and technology allowed for a better understanding of the earth. A key finding was paleomagnetic stripes on the ocean floor which proved that the earth’s crust, and the continents must be moving. This, combined with other evidence helped construct the modern theory of plate tectonics.
I once worked as a driver helper for ups and my selfish dipshit driver refused to let me have breaks or use the bathroom. I had to beg someone I delivered a package to to use theirs after 12 hours with no break. I quit the next day.