Conversation so far:
What happened to Charlie Macartney post-World War I?
After the war, Macartney transformed himself into one of the greatest batsmen of his era.
What is Test cricket?
Test cricket is the form of the sport of cricket with the longest match duration, and is considered the game's highest standard.
How did World War I affect Charlie Macartney's cricketing career?
The war years divided Macartney's career in two.
How was Charlie Macartney cricketing career different after World War I?
After the war, Macartney transformed himself into one of the greatest batsmen of his era.
Did Charlie Macartney fight in World War I?
In January 1916, he enlisted in the Australian Imperial Force.

Question: Where did he serve?
Self-contained rewrite: Where did Charlie Macartney serve in World War I?