civil war
Zeppelins bro
The greatest impact on Canada was as a result of World War II due to Canada's extensive effort in this war as opposed to World War I.
Spain had the greatest impact on Latin America.
It is probably impossible to argue what had the greatest impact on world history, it did of course have a massive impact and we still see its legacy now, but there are other things that have had an impact that is still with us (from the Roman Empire through to the Cold War). I think this probably counts as either a question that cannot be answered, or one that should be answered simply as "No".
electrisity
civil war
cell phones
the Americans
Zepplins
WW1
it has nothing impact...
Fourteenth Amendment
_There should be a space between 'the' and 'impact' it should read: "What was the impact of World War 2 on US society?" Soz!_
waning support for the war in the US
Zeppelins bro
The telegraph
Rifle