Rapid industrialization saw the growth of wealth among countries in Europe. However, they needed more resources to maintain or expand their industries. At the same time, they wanted to protect their economic interests as countries competed with each other for more economic power. As a result, militarism took root. Out of protection, industrial factories started producing weapons to protect countries should conflicts arise. This only produced the opposite as effect as neighbor saw this as a sign of aggression. In the end it together with other causes such as rival alliances and nationalism would lead to World War I.