Why did the Second World War happen?

There were
two reasons for the start of .

First, and most importantly, there were three
countries, two of whom were major powers, that were very dissatisfied with the status quo in the
world after World War I.  These countries were Germany, Italy, and Japan.  Germany had been on
the losing side in WWI and had been harshly punished by the Treaty of Versailles.  It wanted to
get back to what it saw as its...