WWI implemented trench warfare. Instead of everyone standing in a line people got down in trenches and fought each other. They would stay in these trenches for extended periods of time. The trenches were usually dirty and crowded.
Image result for The French Revolution (1789) began as a reaction to
The French Revolution began in 1789 and lasted until 1794. King Louis XVI needed more money, but had failed to raise more taxes when he had called a meeting of the Estates General. This instead turned into a protest about conditions in France.
Cited: https://www.nationalarchives.gov.uk/education/resources/french-revolution/
Allies and aides I think those are good
B. Islam. Islam is still found commonly in North Africa and the Middle East.
