The start of plate tectonics.
Alfred Wegener was the first to discover plate tectonics. He found that two continents could fit together(Africa and South America). Most scientists disagreed with this theory because they thought it isn't possible. Some people did support it. Alexander du Toit and Arthur Holmes did support him.
The plate boundaries are convergent , divergent , and transform. Convergent boundaries are when two plates overlap. divergent boundaries are when two plates spread and form new crust. Transform boundaries are when two plates slide against each other. Lots of things form from plate boundaries such as mountains.The movement between them can cause earthquakes. Asia has all three plate boundaries in it.