The original Armistice Day, later known as Veterans' Day in the US.

Question

I've posted this clip before, but I never fail to get teary listening to it.

A salute, and blessings to all our vets. 

Answer 1

Serbia won two German allies: Bulgaria and Astria - Hungary.

Answer 2

Живела Србија!

Answer 3

The War to end all wars!

That'll be the day, pilgrim!

Answer 4

Sad, but true. And our best pay the awful price.