Deadliest Conflict in Human History World War II was the biggest and deadliest war in human history, lasting six years, and ...

Narrator: The Second World War was the largest war every fought ... like Morocco and Algeria and beyond. Two other countries also joined sides with Nazi Germany, Italy and Japan.

This is because it led to the development of even more powerful weapons and because it had a huge impact on relationships between countries. After World War Two, there was a lot of tension between ...