Wow, I always thought that plate tectonics had been figured out way before the 1950's. Not that geologists are behind on the game but the way it was presented to me growing up it was as if they had know this concept for many, many years.
I have to admit, when the concept was first proposed to me as a student in elementary school, I was skeptical. How on Earth, pardon the pun, could we be floating on top of molten magma. When we reach down and touch the ground, if feels so solid. Sure there are areas of mud and loose dirt but the mountains and rock below us give an almost certain feeling of solidity underneath or feat.
I wonder if we will ever travel into the Earth like we do into space. Hopefully it's not all science-fiction.