August 20

• August 20, 1191
  Crusader King Richard I executes some 2,700 Muslim prisoners in Acre
• August 20, 1530
  Hayreddin Barbarossa, a Barbary pirate, unites Algeria and Tunisia as military states under the Ottoman caliphate and becomes admiral of the Ottoman fleet
• August 20, 1619
  The first African slaves arrive to North America aboard a Dutch privateer and dock in Jamestown, Virginia, with twenty human captives among its cargo
• August 20, 1672
  Johan de Witt, Grand Pensionary of Holland and key figure in Dutch politics, is assassinated by a carefully organized lynch mob by a shot in the neck, and his naked body is hanged and mutilated beside body of his brother Cornelis de Witt
• August 20, 1745
  Bonnie Prince Charlie occupies Blair Castle, Scotland
• August 20, 1847
  General Winfield Scott wins the Battle of Churubusco, only 8 kilometers away from Mexico City
• August 20, 1860
  Robert O'Hara Burke leads a group of 15 men, 27 camels and 23 horses out of Melbourne on an expedition to cross Australia
• August 20, 1913
  Adolphe Pégoud becomes the first pilot to parachute from an aircraft
• August 20, 1939
  Soviet forces under Lieutenant General Georgi Zhukov successfully counterattack Japanese invaders at Nomanhan in the Mongolian People's Republic on the border with Manchukuo
• August 20, 1940
  Ramón Mercader, agent of Josef Stalin, fatally stabs Leon Trotsky with an ice pick in Mexico City
• August 20, 1956
  The Calder Hall atomic power station begins operation in Cumberland, Great Britain, generating up to 90,000 kilowatts of power and manufacturing plutonium becoming the world's first power station to generate electricity on an industrial scale
• August 20, 2011
  In the Battle of Tripoli, Libyan rebels take control the nation's capital, effectively overthrowing the government of Muammar Gaddafi

July 30

• July 30, 762
  Al-Mansur, the second Abbasid caliph, founds Baghdad and makes it the capital of Abbasid Caliphate
• July 30, 1178
  Frederick I, Holy Roman Emperor, is crowned King of Burgundy
• July 30, 1358
  Étienne Marcel, a provost of the merchants of Paris and the leader of the Third Estate, is murdered in Paris
• July 30, 1419
  The group of the followers of Jan Hus threw the judge, the burgomaster, and some thirteen council members out of the window of the New Town Hall in Prague triggering Hussite Wars in central Europe
• July 30, 1619
  The first representative assembly in America, the House of Burgesses, becomes the first legislative assembly in America when it convened at Jamestown
• July 30, 1733
  Society of Freemasons opens first American lodge in Boston
• July 30, 1811
  Miguel Hidalgo y Costilla, Mexican hero priest, is executed by Spanish firing squad during Mexican War of Independence
• July 30, 1863
  Henry Ford, founder of the Ford Motor Company and developer of the Model T, is born in Dearborn Township, Michigan
• July 30, 1864
  The town of Chambersburg, Pennsylvania, is burned by Confederate forces under General John McCausland
• July 30, 1930
  The first football world cup, played in Uruguay, is won by Uruguay national football team
• July 30, 1932
  Flowers and Trees, the first commercially released film to be produced in the full-color three-strip Technicolor process, is produced by Walt Disney
• July 30, 1943
  45,000 civilians are killed and practically the entire city destroyed during bombing of Hamburg by the Royal Air Force and United States Army Air Forces
• July 30, 1971
  Lunar Rover is used after Apollo 15 landing on the moon
• July 30, 1980
  British New Hebrides becomes independent and takes name Vanuatu
• July 30, 2000
  Venezuela's president Hugo Chavez is re-elected with 59 percent of the vote
• July 30, 2012
  In the worst power outage in world history, the India blackouts leave 620 million people without power
• July 30, 2012
  In the worst power outage in world history, the India blackouts leave 620 million people without power

June 21

• June 21, 217 BC
  Roman army is ambushed and destroyed by Hannibal's army, numbering around 55,000 troops, at the Battle of Lake Trasimene, which becomes the largest ambush in military history
• June 21, 1377
  Edward III, King of England, dies
• June 21, 1547
  The great fire in Moscow destroys sections of Moscow which had been built almost entirely of wood including some building in the Kremlin
• June 21, 1607
  The Church of England Episcopal Church, the first Protestant Episcopal parish in America, is established at Jamestown
• June 21, 1661
  Sweden signs the Treaty of Cardis, in which Russia agrees to return to Sweden areas it had conquered in the Baltic lands
• June 21, 1675
  Sir Christopher Wren begins to rebuild St Paul's Cathedral in London, replacing the old building which has been destroyed by the Great fire
• June 21, 1749
  English transport ships land 2576 colonists on what is now Nova Scotia to establish a British military base, naming the town Halifax
• June 21, 1788
  New Hampshire ratifies the United States Constitution as the ninth state, and by the terms of Article VII it is in effect
• June 21, 1834
  Obed Hussey, an American inventor, patents mechanical reaping machine
• June 21, 1887
  Britain celebrates the golden jubilee of Queen Victoria
• June 21, 1893
  George Washington Gale Ferris, engineer, completes the construction of a 77-meter high revolving steel wheel with 38 passenger cars, each with 40 plush chairs, for the World's Columbian Exposition in Chicago, the first Ferris wheel
• June 21, 1897
  In Austria a giant Ferris wheel, designed by Walter Bassett of England, is opened in Vienna to commemorate the 50th anniversary of the accession of Emperor Franz Joseph to the Habsburg throne
• June 22, 1940
  After German blitz France formally surrenders at the signing ceremony, held in the same wagon-lit railroad car used by French Marshal Ferdinand Foch to accept the surrender of Germany in 1918
• June 21, 1948
  In a lab in Manchester, England, the Small Scale Experimental Machine computer, nicknamed "Baby" is created, the first to contain memory (128 bytes) which could store a program
• June 21, 1985
  It is confirmed by American, German, and Brazilian forensic pathologists that the body exhumed in Brazil on June 6 is, indeed, that of the German physician in Auschwitz concentration camp, Josef Mengele