1860 – A Frenchman named Édouard-Léon Scott de Martinville (1817-1879; aka, Leon Scott) used a phonautograph to create what would eventually become recognized as the oldest audible recording of a human voice.
The phonautograph itself, patented by Scott some three years earlier, was intended to transcribe sound into "a visible medium," but the device had no means for playback. As a result, the transcriptions would not be heard until computer technology essentially created a way in 2008. The resulting sound was a barely recognizable 10-second recording of the French folk song "Au Clair de la Lune," believed to have been sung by Scott himself.
1865 – Robert E. Lee surrendered the Army of Northern Virginia to Ulysses S. Grant at Appomattox Courthouse, effectively ending the War Between the States.
"Governor, if I had foreseen the use those people designed to make of their victory, there would have been no surrender at Appomattox Courthouse; no sir, not by me. Had I foreseen these results of subjugation, I would have preferred to die at Appomattox with my brave men, my sword in my right hand."
-- General Robert E. Lee, speaking to former Governor of Texas, Fletcher S. Stockdale, less than one month before Lee's death; as quoted in The Life and Letters of Robert Lewis Dabney
1867 – Passing by a single vote, the U.S. Senate ratified a treaty that allowed for the purchase of Alaska from the Russian Empire. Bought for $7.2 million, the area that would become the 49th State (92 years later) came at less than two cents per acre.
1980 – Saddam Hussein had philosopher Muhammad Baqir al-Sadr executed after three days of torture, essentially for the endorsement of a political philosophy known as Wilayat Al-Umma ("Governance of the people"). Chants of "Long live Mohammed Baqir Sadr!" were chanted by Shi'a guards just prior to Saddam Hussein's execution on December 30, 2006.
1992 – In one of the great political surprises of the 20th century, John Major's Conservative Party won an unprecedented fourth general election victory in the United Kingdom.
2003 – Baghdad fell to Coalition forces amid the American-led invasion of Iraq. To bloody hell with Saddam Hussein.
Initially published 4/9/10; information obtained via Wikipedia and confirmed through various sources.