The First World War was an international conflict that lasted four years and killed millions. It is considered to be one of the deadliest wars in history.

The conflict was triggered by an assassination in Sarajevo, Serbia. This act was followed by military tensions between Russia and Austria-Hungary, leading to the declaration of a state of war on September 28, 1914.

Economic turmoil in the late 19th century created a wave of aggressive nationalism that spread across Europe. This nationalism fueled the rise of Germany and Fascist Italy, both of which sought to reassert their dominance over European society.

As nations tried to cope with these changes, they began to mobilize troops and military machinery to fight their opponents. But this was not a straightforward process.

A few major trends had a strong impact on how quickly countries would mobilize, including the spread of industrialization, which brought modern weapons and tactics to warfare. Other trends included the concept of national sovereignty and aggressive nationalism.

Using the latest technology, governments and diplomats could quickly move troops and military equipment. But the speed of these movements was a problem.

This led to massive casualties and a war that was often fought with faulty tactics. For example, soldiers flocked to the trenches in France and pushed forward with massed charges only to suffer high casualties in battle. This type of warfare did not work when faced with machine guns, barbed wire, and greatly improved artillery.