21 July
1942 — Japanese troops landed at Buna and Gona, New Guinea.
1943 — The Battle of Roosevelt Ridge began on New Guinea.
1969 — HMAS Perth received a United States Navy Unit Commendation for service in Vietnam.
1942 — Japanese troops landed at Buna and Gona, New Guinea.
1943 — The Battle of Roosevelt Ridge began on New Guinea.
1969 — HMAS Perth received a United States Navy Unit Commendation for service in Vietnam.
1916 — The Battle of Fromelles concluded in France.
1943 — HMAS Hobart survived a torpedo hit.
1944 — Nazi officers attempted to assassinate Adolf Hitler.
1900 — The Battle of Palmietfontein, South Africa.
1916 — The Battle of Fromelles began in France.
1940 — The Battle of Cape Spada, off Greece.
1942 — Australian troops captured Trig 22 during the First Battle of El Alamein, Egypt.
1960 — The first junior recruits began training at HMAS Leeuwin.
1945 — HMAS Quiberon and Quickmatch bombarded Japan.
1945 — The Potsdam Conference began.
1976 — East Timor was annexed by Indonesia.
1940 — HMAS Waterhen and Borella bombarded Bardia.
1943 — The Battle of Mount Tambu began on New Guinea.
1945 — The Trinity nuclear test was conducted in the United States.
1918 — HMAT Barunga was sunk.
1940 — The Volunteer Defence Force was formed.
1945 — No. 452 Squadron, RAAF, arrived on Borneo.
1918 — The Battle of Abu Tellul, Palestine.
1941 — An Armistice ended the Syria-Lebanon Campaign.
1943 — Australian troops seized Mubo, New Guinea.
1943 — The Battle of Kolombangara, Solomon Islands.
1943 — HMAS Nizam rescued 13 shipwrecked Americans.
1953 — HMAS Tobruk began her last patrol of the Korean War.
1863 — The invasion of Waikato began during the Māori Wars.
1918 — Konigsberg was sunk in Tanzania.
1941 — Australian troops captured Beirut, Lebanon.
1965 — Troops of 3RAR fought Indonesian troops at Babang, Borneo.
2006 — Australian troops conducted a major raid in the Chora Valley, Afghanistan.