How many countries took part in world war 1
- How many countries was in world war 1
- How many countries involved in world war 1
- How many countries take part in world war 1
- Countries took part in world war 1
- How many countries fought in world war 1
- How many countries fought in world war 1 and 2
- How many countries included in world war 1
- How many countries participated in world war 1 and 2