World War I was a global conflict fought during the years of 1914-1918. It involved many of the worlds greatest and most powerful countries of the time. There were many causes that led up to the war, including nationalism among citizens, militarism, imperialism, and alliances.
There were 2 major 'teams' or alliances during WWI. The Alliance, as they were called, was made up of many countries which included France, Russia, England and later, the US. The enemies, the Central Powers, were made up of countries like the Austria-Hungarian Empire, Germany, and Turkey.
Prior to WWI, the Austria-Hungarian and German Empires had many imperialist ventures. They both wanted more territory added to their empires. It wasn't long before AH wanted to take control over Serbia, a small country just south of their border. Some Serbian nationalists had too much pride to give up their small country at the will of a power-hungry archduke, and stood up to the AH empire, refusing to hand over their land. This led to the Archduke making a visit to the country to show his good nature, oblivious to his impending doom that was near.
The archduke, Franz Ferdinand, had been traveling through Serbia when his car was first attacked. A bomb was thrown in an attempt to assassinate him, but missed and injured many bystanders. Because he was so persistent in showing the country how much of a good guy he was, he insisted on visiting the injured persons in the hospital, which resulted in one of his assassins spotting his car by chance, and killing both the archduke, and his pregnant wife. The assassination proved to be a successful way to stop the AH empire from acquiring Serbia.
The assassination of Franz Ferdinand led to an angry Austria-Hungary demanding Serbia hand over the killer. After many refusals, the AH empire waged war upon Serbia, thus beginning World War I.
After the declaration on Serbia, Germany decided to back up their neighbor and joined up with the Austria-Hungarian empire creating the Central Power alliance. France decided that their best choice would be to join Serbia's side and fight against AH and German empires.
Eventually, as different countries declared which side they were a part of, Belgium declared its neutrality.
