This Is The Largest Known Insect of All Time, With a Wingspan of 2.5 ft (75 cm)

But why aren’t there such gigantic dragonflies in today’s world? What was that allowed griffinflies to attain their great size?

The Late Paleozoic period of Earth’s past was unusual in more than one way. During the Late Carboniferous and Early Permian there existed extensive coal swamp forests that created tremendous amounts of oxygen as a byproduct of photosynthesis. This created a hyperoxic atmosphere, with oxygen levels far in excess of modern levels.