It's called debt. I think of debt as in the red, the negative zone.
I hope I helped :)
The Nile was most important to the Egyptians because it delivered water and nutrients for the crops that were grown along the beds of the river itself.
"wealthy landowners" were members of the aristocracy in Byzantine society since this aristocracy was composed a small elite. The shopkeepers and small-scale merchants constituted the poor majority.
Since then the Great Wall was built, rebuilt to protect the northern borders of the Chinese Empire from the Hun's and Mongolian attacks during the rule of successive dynasties.
