Gallipoli, a battle and siege in Turkey during WWI is fundamental to Australian history. One of the Australian Prime Ministers said that Australia established itself as a nation through its role and valor at Gallipoli. ANZAC Day (25 April) was originally established in 1916 to commemorate the battle at Gallipoli. ANZAC Day is now officially a commemoration of soldiers from all wars (much like the US Memorial Day), and is one of Australia's most important holidays.
I liked the number of exhibits that were actual art, not just documentary material. Australia had a number of artists who are designated as official war artists (they continue this tradition today - see paintings from Iraq and Afghanistan here). Many of the photos I took were of bronzes made of scenes in the war.
I am having some technical problems with blog formatting and will do an update later with more info on some of the specific photos.