April 18 is the 108th day of the year (109th in leap years) in the Gregorian calendar. There are 257 days remaining until the end of the year.
- 1025 - Bolesław Chrobry is crowned in Gniezno, becoming the first King of Poland.
- 1506 - The cornerstone of the current St. Peter's Basilica is laid.
- 1518 - Bona Sforza is crowned as queen consort of Poland.
- 1738 - Real Academia de la Historia ("Royal Academy of History") founded in Madrid.
- 1775 - American Revolution: The British advancement by sea begin; riders warn of impending arrests of Samuel Adams and John Hancock.
- 1783 - Fighting ceases in the American Revolution, eight years to the day since it began.
- 1797 - The Battle of Neuwied - French victory against the Austrians.
- 1848 - American victory at the battle of Cerro Gordo opens the way for invasion of Mexico.
- 1880 - An F4 tornado strikes Marshfield, Missouri, killing 99 people and injuring 100.
- 1881 - Billy the Kid escapes from the Lincoln County jail in Mesilla, New Mexico.
- 1899 - The St. Andrew's Ambulance Association is granted a Royal Charter by Queen Victoria.
- 1902 - Quetzaltenango, second largest city of Guatemala, destroyed by Earthquake.
- 1906 - The 1906 San Francisco earthquake and fire destroys much of San Francisco, California.
- 1906 - The Los Angeles Times story on the Azusa Street Revival launches Pentecostalism as a worldwide movement.
- 1909 - Joan of Arc is beatified in Rome.
- 1912 - The Cunard liner RMS Carpathia brings 705 survivors from the RMS Titanic to New York City.
- 1915 - French pilot Roland Garros is shot down and glides to a landing on the German side of the lines during World War I.
- 1923 - Yankee Stadium, "The House that Ruth Built", opens.
- 1924 - Simon & Schuster publishes the first Crossword Puzzle book.
- 1942 - World War II: The Doolittle Raid on Japan. Tokyo, Yokohama, Kobe and Nagoya bombed.
- 1942 - Pierre Laval becomes Prime Minister of Vichy France.
- 1943 - World War II: Operation Vengeance, Admiral Isoroku Yamamoto is killed when his aircraft is shot down by U.S. fighters over Bougainville Island.
- 1945 - Over 1,000 bombers attack the small island of Heligoland, Germany.
- 1945 - Diplomatic relations between the Soviet Union and Bolivia are established.
- 1946 - The League of Nations is dissolved.
- 1949 - The Republic of Ireland Act comes into force.
- 1949 - The aircraft carrier USS United States (CVA-58)Template:WP Ships USS instances is laid down at Newport News Drydock and Shipbuilding. However, the United States is canceled five days later, resulting in the Revolt of the Admirals.
- 1954 - Gamal Abdal Nasser seizes power in Egypt.
- 1955 - Twenty-nine nations meet at Bandurg, Indonesia, for the first Asian-African Conference.
- 1958 - A United States federal court rules that poet Ezra Pound is to be released from an insane asylum.
- 1961 - CONCP is founded in Casablanca as a united front of African movements opposing Portuguese colonial rule.
- 1974 - The Prime Minister of Pakistan Zulfikar Ali Bhutto inaugurates Lahore Dry port.
- 1980 - The Republic of Zimbabwe (formerly Rhodesia) comes into being, with Canaan Banana as the country's first President.
- 1983 - A suicide bomber destroys the United States embassy in Beirut, Lebanon, killing 63 people.
- 1988 - The United States launches Operation Praying Mantis against Iranian naval forces in the largest naval battle since World War II.
- 1992 - General Abdul Rashid Dostum revolts against President Mohammad Najibullah of the Democratic Republic of Afghanistan and allies with Ahmed Shah Massoud to capture Kabul.
- 1993 - President of Pakistan, Ghulam Ishaq Khan dissolves the National Assembly and dismisses the Cabinet.
- 1996 - In Lebanon, at least 106 civilians are killed when the Israel Defense Forces shell the UN compound at Quana where more than 800 civilians had taken refuge.
- 1999 - Wayne Gretzky, Canadian hockey great, retires at his final home game with the New York Rangers.
- 2007 - The Supreme Court of the United States upholds the Partial-Birth Abortion Ban Act in a 5-4 decision.
- 1480 - Lucrezia Borgia, Florentine ruler and daughter of Pope Alexander VI (d. 1519)
- 1580 - Thomas Middleton, English dramatist (d. 1627)
- 1590 - Ahmed I, Ottoman Emperor (d. 1617)
- 1605 - Giacomo Carissimi, Italian composer (d. 1674)
- 1771 - Karl Philipp Fürst zu Schwarzenberg, Austrian field marshal (d. 1820)
- 1772 - David Ricardo, English economist (d. 1823)
- 1797 - Adolphe Thiers, French statesman (d. 1877)
- 1813 - James McCune Smith, African-American doctor and abolitionist (d. 1865)
- 1819 - Carlos Manuel de Céspedes, Cuban Revolutionary (d. 1874)
- 1819 - Franz von Suppé, Austrian composer (d. 1895)
- 1838 - Paul Emile Lecoq de Boisbaudran, French scientist (d. 1912)
- 1857 - Clarence Darrow, American attorney (d. 1938)
- 1863 - Leopold Graf Berchtold, Austro-Hungarian foreign minister (d. 1942)
- 1864 - Richard Harding Davis, American author (d. 1916)
- 1874 - Oskar Ernst Bernhardt, German author (d. 1941)
- 1875 - Ivana Brlic-Mazuranic, Croatian writer (d. 1938)
- 1877 - Vicente Sotto, Filipino patriot, author (d. 1950)
- 1880 - Sam Crawford, baseball player (d. 1968)
- 1882 - Leopold Stokowski, Polish conductor (d. 1977)
- 1888 - Duffy Lewis, American baseball player (d. 1979)
- 1889 - Jessie Street, Australian suffragette, feminist, and human rights activist (d. 1970)
- 1893 - Violette Morris, French athlete (d. 1944)
- 1897 - Ardito Desio, Italian topographer (d. 2001)
- 1901 - Al Lewis, American lyricist (d. 1967)
- 1902 - Giuseppe Pella, Prime Minister of Italy (d. 1981)
- 1902 - Menachem Mendel Schneerson, Hasidic Judaism leader (d. 1994)
- 1904 - Pigmeat Markham, American comedian (d. 1981)
- 1905 - George H. Hitchings, American scientist, Nobel laureate (d. 1998)
- 1907 - Miklós Rózsa, Hungarian-born composer (d. 1995)
- 1915 - Joy Gresham Lewis, American writer, wife of C. S. Lewis (d. 1960)
- 1917 - Ty LaForest, Canadian baseball player (d. 1947)
- 1917 - Frederika of Hanover, Queen Consort of Greece (d. 1981)
- 1918 - Cliff Hillegass, American publisher (d. 2001)
- 1918 - Tony Mottola, American guitarist (d. 2004)
- 1919 - Virginia O'Brien, American singer and actress (d. 2001)
- 1921 - Jean Richard, French actor (d. 2001)
- 1922 - Barbara Hale, American actress
- 1924 - Clarence "Gatemouth" Brown, American musician (d. 2005)
- 1924 - Henry Hyde, American politician (d. 2007)
- 1927 - Samuel P. Huntington, American political scientist
- 1930 - Clive Revill, New Zealand born actor
- 1934 - George Shirley, American tenor
- 1936 - Tommy Ivo, American race car driver
- 1937 - Jan Kaplický, British architect of Czech origin
- 1939 - Ali Khamenei, the Supreme Leader of the Islamic Republic of Iran
- 1939 - Thomas J. Moyer, American judge
- 1940 - Joseph L. Goldstein, American scientist, Nobel laureate
- 1940 - Mike Vickers, British guitarist and saxophonist (Manfred Mann)
- 1942 - Jochen Rindt, German-Austrian racer and F1 (posthumous) world champion (d. 1970)
- 1942 - Steve Blass, American professional baseball player
- 1945 - Margaret Hassan, Irish-born aid worker (d. 2004)
- 1946 - Hayley Mills, English actress
- 1946 - Skip Spence, Canadian-born guitarist, singer and songwriter (Jefferson Airplane) (d. 1999)
- 1947 - Kathy Acker, American author (d. 1997)
- 1947 - Dorothy Lyman, American actress
- 1947 - Herbert Mullin, American serial killer
- 1947 - Cindy Pickett, American actress
- 1947 - James Woods, American actor
- 1949 - Geoff Bodine, American race car driver
- 1950 - Kenny Ortega, American film and TV producer and choreographer
- 1951 - Ricardo Fortaleza, Australian-Filipino boxer
- 1951 - Pierre Pettigrew, Canadian politician
- 1953 - Rick Moranis, Canadian comedian
- 1956 - Anna Kathryn Holbrook, American actress
- 1956 - Eric Roberts, American actor
- 1956 - Melody Thomas Scott, American actress
- 1956 - Poonam Dhillon, Indian actress
- 1958 - Malcolm Marshall, Barbadian West Indies cricketer (d. 1999)
- 1961 - Jane Leeves, British actress
- 1961 - Steve Lombardi, American wrestler
- 1963 - Eric McCormack, Canadian actor
- 1963 - Conan O'Brien, American comedian
- 1964 - Niall Ferguson, British historian
- 1964 - Rithy Panh, Cambodian film director
- 1964 - Jim Ellison, musician
- 1964 - Mark Berry, aka Bez, Dancer in Happy Mondays
- 1965 - Rob Stenders, Dutch radio discjockey
- 1966 - Trine Hattestad, Norwegian athlete
- 1966 - Valeri Kamensky, Russian ice hockey player
- 1967 - Maria Bello, American actress
- 1968 - Mary Birdsong, American actress
- 1968 - David Hewlett, English born Canadian actor
- 1969 - Princess Sayako of Japan
- 1969 - Keith R.A. DeCandido, American author
- 1970 - Greg Eklund, American musician
- 1970 - Rico Brogna, American baseball player
- 1971 - Tamara Braun, American actress
- 1971 - Russell Payne, English writer
- 1971 - David Tennant, Scottish actor
- 1971 - Oleg Petrov, Russian ice hockey player
- 1972 - Rosa Clemente, American activist and hip-hop artist
- 1972 - Eli Roth, American film director
- 1973 - Derrick Brooks, American football player
- 1973 - Haile Gebrselassie, Ethiopian athlete
- 1973 - Brady Clark, American baseball player
- 1974 - Mark Tremonti, American musician
- 1974 - Millie Corretjer, Puerto Rican singer
- 1974 - Edgar Wright, British director
- 1976 - Melissa Joan Hart, American actress
- 1976 - Fayray, Japanese singer
- 1976 - Justin Ross, American politician
- 1977 - Dan Lacouture, NHL hockey player
- 1979 - Michael Bradley, American basketball player
- 1979 - Anthony Davidson, British Formula One driver
- 1979 - Nuria Fergó, Spanish singer
- 1979 - Matthew Upson, English footballer
- 1979 - Kourtney Kardashian, American reality television star
- 1980 - Robyn Regehr, Canadian ice hockey player
- 1981 - Brian Buscher, American baseball player
- 1982 - Marie-Élaine Thibert, Canadian singer
- 1982 - Scott Hartnell, NHL hockey player
- 1983 - Miguel Cabrera, Venezuelan baseball player
- 1983 - Fodil Hadjadj, Algerian footballer
- 1984 - America Ferrera, American actress
- 1985 - Łukasz Fabiański, Polish footballer
- 1985 - Karl Reindler, Australian racing driver
- 1985 - Elena Temnikova, Russian singer (Serebro)
- 1986 - Maurice Edu, American soccer player
- 1986 - Billy Butler, American baseball player
- 1987 - Brett Deledio, Australian Rules Football
- 1987 - Danny Guthrie, English footballer
- 1987 - Sandra Lyng Haugen, Norwegian singer
- 1989 - Alia Shawkat, American actress
- 1989 - Simas Buterlevičius, Lithuanian basketball player
- 1994 - Moises Arias, American Actor
- 1996 - Alexey Zhigalkovich, Belarusian Singer
- 2007 - Hayah bint Hamzah, Princess of Jordan
- 1161 - Theobald of Bec, Archbishop of Canterbury
- 1552 - John Leland, English antiquarian (b. 1502)
- 1556 - Luigi Alamanni, Italian poet (b. 1495)
- 1567 - Wilhelm von Grumbach, German adventurer (b. 1503)
- 1558 - Roxelana, wife of Suleiman the Magnificent
- 1636 - Julius Caesar, English judge
- 1650 - Simonds d'Ewes, English antiquarian (b. 1602)
- 1674 - John Graunt, English statistician (b. 1620)
- 1689 - George Jeffreys, British Chief Justice (b. 1648)
- 1732 - Louis Feuillée, French explorer (b. 1660)
- 1794 - Charles Pratt, 1st Earl Camden, Lord Chancellor of Great Britain (b. 1714)
- 1796 - Johan Wilcke, Swedish physicist (b. 1732)
- 1802 - Erasmus Darwin, English physician and botanist (b. 1731)
- 1873 - Justus von Liebig, German chemist (b. 1803)
- 1898 - Gustave Moreau, French painter (b. 1826)
- 1906 - Luis Martín, Spanish Superior-General of the Society of Jesus (b. 1846)
- 1917 - Vladimir Serbsky, Russian psychiatrist (b. 1858)
- 1935 - Panait Istrati, Romanian writer (b. 1884)
- 1936 - Ottorino Respighi, Italian composer (b. 1879)
- 1942 - Gertrude Vanderbilt Whitney, American socialite (b. 1875)
- 1943 - Isoroku Yamamoto, Japanese admiral. (b. 1884)
- 1945 - John Ambrose Fleming, English physicist and engineer (b. 1849)
- 1945 - Ernie Pyle, American journalist (b. 1900)
- 1945 - Prince William of Wied, sovereign Prince of Albania (b. 1876)
- 1947 - Josef Tiso, Slovakian leader (b. 1887), Nazi collaborator and puppet ruler.
- 1949 - Will Hay, English comedian and actor (b. 1888)
- 1951 - António Óscar Carmona, 97th Prime Minister of Portugal and 11th President of Portugal (b. 1869)
- 1955 - Albert Einstein, Nobel laureate (b. 1879)
- 1958 - Maurice Gamelin, French general (b. 1872)
- 1963 - Meyer Jacobstein, American politician (b. 1880)
- 1964 - Ben Hecht, American writer (b. 1894)
- 1965 - Guillermo González Camarena, Mexican inventor (b. 1917)
- 1967 - Karl Miller, German footballer (b. 1913)
- 1974 - Marcel Pagnol, French novelist, playwright and filmmaker (b. 1895)
- 1976 - Mahmoud Younis, Suez Canal nationalization Engineer (b. 1911)
- 1988 - Pierre Desproges, French humorist (b. 1939)
- 1990 - Gory Guerrero, professional wrestler (b. 1921)
- 1992 - Benny Hill, British comedian (b. 1924)
- 1993 - Masahiko Kimura, Japanese judoka (b. 1917)
- 1995 - Arturo Frondizi, President of Argentina (b. 1908)
- 1996 - Brook Berringer, American football player (b. 1973)
- 1996 - Bernard Edwards, American record producer (b. 1952)
- 1998 - Terry Sanford, American politician (b. 1917)
- 2002 - Thor Heyerdahl, Norwegian explorer (b. 1914)
- 2002 - Wahoo McDaniel, American football player and professional wrestler (b. 1938)
- 2003 - Edgar F. Codd, English computer scientist (b. 1923)
- 2004 - Ratu Sir Kamisese Mara, first Prime Minister of Fiji and President of Fiji (b. 1920)
- 2005 - Sam Mills, American football player (b. 1959)
- 2007 - Iccho Itoh, mayor of Nagasaki (b. 1945)
In the Roman Catholic Church:
