World War II led to the deaths of millions of people in combat and in Nazi work and concentration camps. WW II left millions more homeless and dispossessed.

The largest number of American battle deaths occurred in the European Theater. On the beaches of Normandy and at the Battle of the Bulge are just a couple of places where these deaths occurred. An ebook about this subject is available for download at Lulu.com. Its title is "The High Price of Freedom: The American Graves Registration Command in Europe After World War II."

World War II also had a few positive effects, besides the deaths of millions. It led to the creation of the European Union. People learned that in order to prevent the outbreak of another war, Europe needed to be united.

It led to many technological developments such as the Atomic Bomb (How positive this effect is can be debatable).

It made people more wary towards politicians. I'm not sure of many examples of this, but here in Ireland a group formed shortly after the war called the Blueshirts. As soon as our government saw them using the Fascist salute the organisation was disbanded.

So, not all the aftermath was negative.