PrimeWire

TOALLY agree , there hve 5 prior extinction we would call Massive

End Ordovician (444 million years ago; mya) oxygen
Late Devonian (360 mya)  gapid and severe global cooling.
End Permian (250 mya)  caused global warming. Elevated CO2 and sulfur (H2S) levels from volcanoes ocean acidification, [no oxygen in hot water] acid rain, 
End Triassic (200 mya) – many people mistake this as the event that killed off the dinosaurs. But in fact, they were killed off at the end of the Cretaceous period – the fifth of the "Big Five".
End Cretaceous (65 mya) – the event that killed off the dinosaurs.

Finally, at the end of the timeline, we have the question of what will come. we are nearly close to tipping point for the 6th, and we’ve only been here a minute but the planet will still grow back when we are gone