There were many things that lead up to the first world war, but the main three were:
1. Empires
2.Arms race
3.Allience
1. Empires
2.Arms race
3.Allience
Empires
Empires can become a cause of conflict because they often want to expand. But if there are lots of different empires in one area, they will probably fight for more land and power.
Arms race
In coastal countries in particular, navies are important and before the first world war England built 29 battle ships and Germany had 17. As a result it put pressure on Britain to keep ahead of Germany in numbers of boats and Britain also wondered when Germany would attack.
Alliance
Before the war, Europe was divided into to Alliances. Germany and Britain both had different alliances called : "The triple Entente" and "The triple Alliance".
The triple Entente included: France, Russia and Britain. And the triple alliance included: Germany, Austria-Hungary and Italy
The triple Entente included: France, Russia and Britain. And the triple alliance included: Germany, Austria-Hungary and Italy