August 17

• August 17, 1743
  By the Treaty of Åbo, Sweden cedes southeast Finland to Russia, ending Sweden's failed war with Russia
• August 17, 1786
  Frederick the Great, King of Prussia, dies, and his nephew Frederick William II succeeds
• August 17, 1807
  Robert Fulton's North River Steamboat, popularly known as the Clermont, begin heading up New York's Hudson River on its successful round-trip to Albany and becomes the first commercially successful steamboat
• August 17, 1812
  Napoleon Bonaparte's army defeats the Russians at the Battle of Smolensk during the Russian retreat to Moscow
• August 17, 1869
  Oxford beats Harvard on the Thames River in the first international boat race
• August 17, 1877
  Asaph Hall, an American astronomer, discovered the Mars moon Phobos
• August 17, 1945
  Indonesia declares independence from Netherlands
• August 17, 1960
  Gabon gains independence from France
• August 17, 1970
  Venera 7, the first man-made spacecraft to land successfully on another planet, and to transmit data from there back to Earth, is launched by USSR
• August 17, 1982
  The first commercially available compact discs are released to the public in Germany
• August 17, 1987
  Rudolf Hess, a prominent politician in Nazi Germany, commits suicide by hanging himself with an electrical flex in his cell at age 93 in Spandau Prison in Berlin, Germany, where he served 46 years
• August 17, 1998
  Decline in commodity prices triggers financial crisis in Russia and discredits the government of President Boris Yeltsin
• August 17, 2008
  Michael Phelps wins his record eighth gold medal of the Beijing Games, in the 4x100 medley relay, in record time of 3:29.34 and holds the record for most gold medals at an Olympics event

April 18

• April 18, 1506
  The cornerstone of new St. Peter's Basilica is laid by order of Pope Julius II after demolition of the ancient basilica
• April 18, 1521
  Martin Luther confronts the emperor Charles V in the Diet of Worms and refuses to retract his views which led to his excommunication
• April 18, 1663
  Osman declares war on Austria beginning Austro-Turkish War
• April 18, 1688
  Jacobite army begins siege of Derry in Ireland
• April 18, 1888
  The Imperial British East Africa Company, the administrator of British East Africa, is incorporated in London, England
• April 18, 1906
  At 5:13 a.m., an earthquake estimated 8.0 on the Richter scale strikes San Francisco, caused by a slip of the San Andreas Fault over a segment about 275 kilometers long, killing estimated 3,000 people from the quake and fires and destroying over 80% of the city
• April 18, 1924
  First crossword puzzle book is published in USA by Simon and Schuster
• April 18, 1949
  Republic of Ireland withdraws from British Commonwealth
• April 18, 1951
  France, West Germany and Benelux form European Steel and Coal Community by Treaty of Paris, making one more step to the founding of the European Union
• April 18, 1974
  Red Brigade, a paramilitary organization, kidnaps Italian Attorney General Mario Sossi
• April 18, 1980
  Zimbabwe, formerly Southern Rhodesia, declares independence from United Kingdom and Robert Mugabe becomes Prime Minister