When the first world war happened
- When did the first world war happened
- When does the first world war happened
- The first world war happened between
- The first world war happened in which year
- The first world war happened between which countries
- What happened when the first world war ended
- What happened when the first world war began
- When was the first and second world war happened
- When did the first and second world war happened
- What happened when the first world war broke out
- What happened when the first world war started
- First world war happened between whom
- First world war happened in which countries
- First world war happened between which two countries
- First world war happened in which century