Siege of Bagdad. It was said that the streets ran yellow with human fat that melted from the heat. 1 million were [unalived] over a couple of days.

Any and all acts commited by the Ustaše or the Khmer Rouge.

If you know what the people in those two organizations did, then I think I said enough. If not, then feel free to do research on them; but let it be known that you won't feel well afterwards.

Everybody forgets about the Taiping Rebellion when the self proclaimed Chinese Jesus started a conflict that [ended] upwards of 30 million people.

custard_caramel: Chinese civil wars were full of war crimes. Soldiers would target farmers to starve out the enemy troops.

*Carthago delenda est*.

Rome wiped one of the great civilizations of the Mediterreanean off the map and salted its ruins so that it could never come back. 'Total war' taken to the furthest extreme.

People citing the R**e of Nanking here reminded me of Romans spending 7 whole days to [unalive] every living thing in the city.

Colonization of Africa. Probably not the worst necessarily, but one with massive and far reaching implications.

An entire continent set back for generations socially, culturally, and economically.

The battle of the Somme was pretty horrific.

Recent_Obligation276: Brit’s took 57k casualties on day 1. For perspective, the US, in 20 years of war in the Middle East post 9/11, only took a little over 20k casualties.