The treaty, negotiated at Phoenice in Epirus, brought a formal close to the First Macedonian War between Rome and Philip V of Macedon. Rome, distracted by its life-or-death struggle against Hannibal in Italy, accepted modest terms, but the peace proved temporary, setting the stage for further Macedonian Wars that would eventually bring Rome into direct control of Greece.

As the audience laughed at a comic line, Booth slipped into the presidential box and fired a single shot from a .44-caliber Derringer into the back of Lincoln's head. He leapt to the stage shouting 'Sic semper tyrannis!' and escaped into the night. Lincoln, unconscious, was carried across the street to a boarding house, where he died the next morning.

Four days into her maiden voyage from Southampton to New York, the 'unsinkable' Titanic grazed an iceberg that buckled steel plates along 300 feet of her starboard hull. Water flooded six of sixteen watertight compartments. Captain Edward Smith ordered lifeboats loaded, but there were seats for barely half the roughly 2,224 people aboard, foreshadowing the disaster to come in the early hours of April 15.

On what became known as 'Black Sunday,' a towering wall of dust and topsoil, whipped up by drought and decades of over-farming, rolled across the Southern Plains, blotting out the sun over an area stretching from the Dakotas to Texas. The storm carried an estimated 300 million tons of topsoil and turned midday into pitch darkness, cementing the Dust Bowl in the national memory.

IBM's 'Programmer's Reference Manual' for FORTRAN (Formula Translation) reached engineers and scientists, marking one of the earliest high-level programming languages ever distributed. Developed by a team led by John Backus, FORTRAN let programmers express calculations in near-mathematical notation rather than laborious assembly code, cutting development time dramatically and helping trigger the software industry as we know it.

About 56 hours into the mission, a stir of an oxygen tank triggered an explosion that knocked out two of the Command Module's three fuel cells and vented oxygen into space. Command Module Pilot Jack Swigert radioed the now-famous line, 'Houston, we've had a problem,' as the crew scrambled to power up the Lunar Module as a lifeboat for the harrowing journey back to Earth.