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.

EXPLAINER: What Is the United Nations? In 1945, not long after the end of World War II, representatives of countries from around the world came together to create the United Nations, hoping it ...