Simply speaking mid ocean ridges were formed when magma wells erupted at places where on earth the ocean floor was pulled apart. There are two ways in which these ridges are formed; namely slab-push and ridge-push. The process simply happens when two separate currents of mantle under the crust collide and move upwards. They erupt in the form of magma where on earth divergent boundaries between two separate tectonic plates meet each other. Amazingly all the mid oceanic ridges form factor of a single connected mid-oceanic ridge system which forms the world's longest mountain range. This exceeds eighty thousand kilometres in length. There are a number of the deep ridges in the world including the East Pacific Rise, Explorer Ridge, Gorda Ridge, Mid-Atlantic Ridge, Central Indian Ridge, Walvis Ridge to name a few.