18 June

618 – Li Yuan becomes Emperor Gaozu of Tang, initiating three centuries of Tang Dynasty rule over China.
1053 – Battle of Civitate: 3,000 horsemen of Norman Count Humphrey rout the troops of Pope Leo IX.
1178 – Five Canterbury monks see what is possibly the Giordano Bruno crater being formed. It is believed that the current oscillations of the Moon's distance from the Earth (on the order of meters) are a result of this collision.
1264 – The Parliament of Ireland meets at Castledermot in County Kildare, the first definitively known meeting of this Irish legislature.
1429 – French forces under the leadership of Joan of Arc defeat the main English army under Sir John Fastolf at the Battle of Patay. This turns the tide of the Hundred Years' War.
1684 – The charter of the Massachusetts Bay Colony is revoked via a scire facias writ issued by an English court.
1757 – Battle of Kolín between Prussian forces under Frederick the Great and an Austrian army under the command of Field Marshal Count Leopold Joseph von Daun in the Seven Years' War.
1767 – Samuel Wallis, an English sea captain, sights Tahiti and is considered the first European to reach the island.
1778 – American Revolutionary War: British troops abandon Philadelphia, Pennsylvania.
1812 – War of 1812: The U.S. Congress declares war on the United Kingdom.
1815 – Napoleonic Wars: The Battle of Waterloo results in the defeat of Napoleon Bonaparte by the Duke of Wellington and Gebhard Leberecht von Blücher forcing him to abdicate the throne of France for the second and last time.
1830 – French invasion of Algeria.
1858 – Charles Darwin receives a paper from Alfred Russel Wallace that includes nearly identical conclusions about evolution as Darwin's own, prompting Darwin to publish his theory.
1859 – First ascent of Aletschhorn, second summit of the Bernese Alps.
1873 – Susan B. Anthony is fined $100 for attempting to vote in the 1872 presidential election.
1887 – The Reinsurance Treaty between Germany and Russia is signed.
1900 – Empress Dowager Longyu of China orders all foreigners killed, including foreign diplomats and their families.
1908 – Japanese immigration to Brazil begins when 781 people arrive in Santos aboard the ship Kasato-Maru.
1908 – The University of the Philippines is established.
1923 – Checker Taxi puts its first taxi on the streets.
1928 – Aviator Amelia Earhart becomes the first woman to fly in an aircraft across the Atlantic Ocean (she is a passenger; Wilmer Stultz is the pilot and Lou Gordon the mechanic).
1930 – Groundbreaking ceremonies for the Franklin Institute are held.
1935 – Police in Vancouver, British Columbia, Canada clash with striking longshoremen, resulting in a total 60 injuries and 24 arrests.
1940 – Appeal of June 18 by Charles de Gaulle.
1940 – "Finest Hour" speech by Winston Churchill.
1945 – William Joyce (Lord Haw-Haw) is charged with treason for his pro-German propaganda broadcasting during World War II.
1946 – Dr. Ram Manohar Lohia, a Socialist, calls for a Direct Action Day against the Portuguese in Goa. A road is named after this date in Panjim.
1953 – The Egyptian Revolution of 1952 ends with the overthrow of the Muhammad Ali Dynasty and the declaration of the Republic of Egypt.
1953 – A United States Air Force C-124 crashes and burns near Tokyo, Japan killing 129.
1954 – Pierre Mendès-France becomes Prime Minister of France.
1965 – Vietnam War: The United States uses B-52 bombers to attack National Liberation Front guerrilla fighters in South Vietnam.
1972 – Staines air disaster – 118 are killed when a plane crashes two minutes after take off from London Heathrow Airport.
1979 – SALT II is signed by the United States and the Soviet Union.
1983 – Space Shuttle program: STS-7, Astronaut Sally Ride becomes the first American woman in space.
1983 – Mona Mahmudnizhad together with nine other Bahá'í women, is sentenced to death and hanged in Shiraz, Iran because of her Bahá'í Faith.
1984 – A major clash between about 5,000 police and a similar number of miners takes place at Orgreave, South Yorkshire, during the 1984-1985 UK miners' strike.
1994 – The Troubles: the Ulster Volunteer Force (UVF) open fire inside a pub in Loughinisland, Northern Ireland, United Kingdom, killing six civilians and wounding five.
1996 – Ted Kaczynski, suspected of being the Unabomber, is indicted on ten criminal counts.
2006 – The first Kazakh space satellite, KazSat is launched.
2009 – The Lunar Reconnaissance Orbiter (LRO), a NASA robotic spacecraft is launched.

Holidays and observances

Autistic Pride Day (International)
Christian Feast Day:
Elizabeth of Schönau
Leontius, Hypatius and Theodulus
June 18 (Eastern Orthodox liturgics)
Evacuation Day (Egypt)
Foundation Day (Benguet)
National Day (Seychelles)
Waterloo Day (United Kingdom)