Tools probably as they show more of the history. They're primary resources.
Architecture may show more religion and political institutions though.
The wheel, plow, and writing (a system which we call cuneiform) are examples of their achievements. The farmers in Sumer created levees to hold back the floods from their fields and cut canals to channel river water to the fields. The use of levees and canals is called irrigation, another Sumerian invention.
It leads to flooding and drought in different areas is not the right answer