Portal:Military history of Australia/Selected anniversaries/May/May 4
- 1917 – World War I: During the Second Battle of Bullecourt the 2nd and 4th Battalions used 30,000 hand grenades in a ten hour period.
- 1966 – Vietnam War: 1st Australian Task Force arrived at Vung Tau on HMAS Sydney and begins preparations to move into Phouc Tuy province.