We have witnessed the most rare event in Earth's history and nobody is talking about it. Primary endosymbiosis has happened 4 times on our planet. The first time, it gave us the mitochondria, developing complex life. The last time, plants developed by gaining the ability of photosynthesis. This time, "The algae Braarudosphaera bigelowii has been found to have absorbed a cyanobacteria called UCYN-A" allowing the newly developed lifeforms to directly pull Nitrogen from the air.