| April 24, 1800 | April 24, 1916 |
| • President John Adams approves legislation to appropriate $5,000 to establish the Library of Congress. The first library catalog, dated April 1802, listed 964 volumes and nine maps. | • On Easter Sunday in Dublin, the Irish Republican Brotherhood, a secret organization of Irish Nationalists, launched the Easter Rebellion, an armed uprising against British rule. Although the British authorities quickly suppressed the uprising, the execution of the Easter Rebellion's leaders and other harsh reprisals served to increase support for the nationalist cause in Ireland. |
| April 25, 1915 | April 25, 1945 |
| • During World War I, Allied soldiers invaded the Gallipoli Penninsula in an unsucessful attempt to take the Ottoman Turkish Empire out of the war. | • Delegates from 45 countries met in San Francisco to organize the United Nations. |
| April 26, 1986 | April 26, 1994 |
| • The world's worst nuclear power plant accident occurs at the Chernobyl nuclear power station in the Soviet Union during an engineering experiment in which 200 control rods were inserted into the reactor at once. The chemical reaction caused an explosion that blew off the heavy steel and concrete lid of the reactor. | • More than 22 million South Africans turned out to cast ballots in the country's first ever multiracial parliamentary elections. An overwhelming majority chose anti apartheid leader Nelson Mandela to lead a new coalition government. |
| April 27, 1865 | April 27, 1966 |
| • The worst maritime disaster in American history occurs when the steamboat Sultana, carrying 2,100 passengers, explodes and sinks in the Mississippi River, killing all but 400 of those aboard. The cause of the blast was determined to be a boiler malfunction. | • The Pennsylvania and New York Central Railroads complete what was then the single biggest merger in U.S. corporate history. Despite its $4 billion in assets, mismanagement and financial difficulties pushed Penn Central to file for bankruptcy in 1970. |
| April 28, 1789 | April 28, 1986 |
| • In the Pacific Ocean, Fletcher Christian , the first mate on the H.M.S. Bounty, led a successful munity against Captain William Bligh and his supporters. Christian and his men sailed back to Tahiti on the Bounty, and some later settled on a remote, unpopulated island. Descendants of the Bounty munineers and the Tahitians still live on the island today. | • The Soviet Union informed the world of the nuclear disaster at Chernobyl, saying the accident damaged a reactor and that aid was being rendered to those affected. |
| April 29, 1854 | April 29, 1945 |
| • By an act of the Pennsylvania legislature, Ashmun Institute, the first college founded solely for African American students, was officially chartered. The institution was later renamed Lincoln University. | • The U.S. Seventh Army's 45th Infantry Division liberates Dachau, the first concentration camp established by Germany's Nazi regime. |
| April 30, 1789 | April 30, 1900 |
| • In New York City, George Washington, America's Revolutionary War leader, was inaugurated as the first President of the modern United States. | • Engineer John Luther "Casey" Jones of the Illinois Central Railroad was killed in a wreck near Vaughan, Miss., after staying at the controls in an effort to save the passengers. |
| May 1, 1931 | May 1, 1960 |
| • New York's 102 story Empire State Building was dedicated. Singer Kate Smith began her long running radio program on CBS. | • The Soviet Union shot down an American U-2 reconaissance plane near Sverdlovsk and captured its pilot, Francis Gary Powers. Imprisoned for espionage, Powers was released by the Soviets in 1962 in exchange for a Soviet spy captured by the United States. |
| May 2, 1945 | May 2, 1994 |
| • The Soviet Union announced the fall of Berlin, and the Allies announced the surrender of Nazi troops in Italy and parts of Austria. | • Nelson Mandela claimed victory in the wake of South Africa's first democratic elections; President F. W. DeKlerk acknowledged defeat. |
| May 3, 1942 | May 3, 1947 |
| • The Battle of the Coral Sea begins between Japanese and American aircraft carriers in the Solomon Islands. It marked the first air naval battle in history, as none of the carriers fired at each other, allowing the planes taking off from their decks to do the fighting. Among the casualties was the U.S, carrier Lexington. | • Japan's postwar constitution goes into effect. The progressive constitution granted universal suffrage, stripped Emperor Hirohito of all but symbolic power, stipulated a bill of rights, abolished peerage and outlawed Japan's right to make war. The document was largely the work of Supreme Allied Commander Douglas MacArthur and his occupation staff. |
| May 4, 1932 | May 4, 1970 |
| • Mobster Al Capone, convicted of Income Tax evasion, entered the federal penitentiary in Atlanta. | • At Kent State University in Ohio, 100 National Gaurdsmen fire their fifles into a group of students, Killing four and wounding 11. Ohio Governor James Rhodes had called on the National Guard to restore order after students protesting the Vietnam War torched the ROTC building on Campus. |
| May 5, 1945 | May 5, 1961 |
| • In the only fatal attack of its kind during World War II, a Japanese balloon bomb exploded on Gearhart Mountain in Oregon, killing the pregnant wife of a minister and five children. | • Navy Commander Alan Bartlett Shepard Jr. was launched into space aboard the Freedom 7 space capsule from Cape Canaveral, Florida, becoming the first American astronaut to travel in space. |