6. Reform
They come together to change something
Process food
Cooking food
Develop language
The effects of the Black Death were many and varied. Trade suffered for a time, and wars were temporarily abandoned. Many labourers died, which devastated families through lost means of survival and caused personal suffering; landowners who used labourers as tenant farmers were also affected.
Without having a timeframe or choices, I would guess it would be the Holocaust which was from 1941-1945 when the German Nazi's rounded up and excecuted Jews (men, women, and children)