Answer:
The European countries at the time were a fuse ready to be blown. Many of the countries wanted to show off their military might, and each had a very strong sense of nationalism.
It started with the assassination of Duke Franz Ferdinand of the Austro-Hungarian Empire and his wife by Princip (a Serbian nationalist) in June of 1914.
Austria-Hungary and Germany then declared war on Serbia, which then set of the huge chain of alliances throughout Europe. This started WWl.
