This photo represents the idea that all continents today were once connected and named Pangea. Although there was evidence this idea was looked down upon back in 1915.

Alfred Wegener came up with this idea of Pangea, but he received no support. The reason being was that Wegener had no idea how the continents drifted apart, only that the continents did drift.

Our Earth has a magnetic field, that is how our compasses know north from south. But, randomly every now and then, every tens of thousands of years to millions, our magnetic field shifts and sometimes flips changing our north to our new "south" on a compass. That is called a magnetic reversal. This is when geologists began connecting dots.

Harry Hess is one of the geologists who figured out the pieces of the puzzle that is the mechanics behind our Earth's plate tectonics. As he investigated the seafloor, it was discovered that there were these "stripes" on the sea floor that alternated. What they discovered was that the stripes were a result of the magnetism surrounding our Earth, they were following regular and reverse polarity patterns. This solidified the idea of sea floor spreading.