While it could be from literally anywhere, I'd assume most of them came from the Soviet Union, Germany, France, and Poland, along with plenty of other smaller countries like Austria, Hungary, and even Greece.
Answer:
the Tigris and Euphrates rivers
Explanation:
Mesopotamia was a very fertile and good area located around and between the two rivers Tigris and Euphrates. The first civilization rose here and many developments and settlements were made. Many technological breakthroughs were made in this area and small towns developed. New agriculture and watering methods were implemented which led to population increase.
