The ingenuity of past civilizations

[Anianna]

We can learn a lot about surviving in place for longer periods from past civilizations.  Our ancestors had a wealth of engineering and food preservation techniques, some of which still exist in pockets of modern civilization but are otherwise lost or largely unknown elsewhere.  Here are a couple of examples:

Century eggs are the result of chemically altering eggs over a period of time so that they are edible in a different state rather than spoiled. 
https://en.wikipedia.org/wiki/Century_egg

Yakhchāl or Persian "ice pit" is a structure where ice could be stored throughout the hottest parts of the year in arid regions and where frozen treats could be produced even in the desert. 
https://en.wikipedia.org/wiki/Yakhch%c4%81l
https://i.redd.it/qqnk7o9dcl2a1.jpg 

[Ever (Zombiepreparation)]

Dang. 🤔

Moar please.