I need more context, but without context you’d often see twin towers
Hydrogen 2 oxygen
aka water
Answer: Citizens of Rome lost their land after many years of drought.
Men who fought in wars could not take care of their farms and often lost their land. The plebeians became powerful but could not govern well.
There was no authority in place to stop soldiers from robbing wealthy Romans.
The Roman Republic lost the territories from which it received most of its taxes.
Hope this helps (:
On the silk road it would be sand storms but normaly it would be invading dynasties