How shall I talk to my son about ANZAC Day?

A 10 year-old wants to know why tomorrow is a special day. I’m struggling to explain it.

I tried to explain ANZAC Day to my son last night. We were updating our countdown to school returning (6 sleeps, 5 sleeps, 4 sleeps) and I was explaining that Friday was a public holiday. It occurred to me that I should explain the significance of the day to him properly because he’s 10 and he should understand this significant part of our nation’s history.

But how to explain war to a child?

He's heard about ANZAC Day before, mostly at school. He's discussed it with me as well. I did my best without going into too much detail but now that he's 10 I feel like he should really grasp the full meaning of it.

The struggle I'm having is in deciding how far to take that explanation. It's one thing to talk about ANZAC Day, explain who the ANZACs were, what World War I was all about, but how about war in general? How do you explain how thousands of young Australian lives could be lost on battlefields? How do I get him to fully comprehend their bravery, their sacrifice and feel properly thankful for the gift of the life he currently enjoys?

My son's inevitable question after I explain war to him will be, "Does that still happen now?" What do I say? "Yes darling, in fact there are people dying right now on battle fields." It's too horrible for me to think about and I'm not sure I want it to be forefront on his mind.

Should it be?

How should I talk to my kids about ANZAC Day?