July 27, 1931: A dry year at the beginning of America's "Dust Bowl" creates the Perfect Swarm, as grasshoppers overwhelm farmland in Iowa, Nebraska and South Dakota. Cornfields are eaten down to the stubs, and American agriculture suffers a disaster at the beginning of the Great Depression.
July 27, 1953: Score one for unintended, good, consequences: As part of their truce, North and South Korea establish a 155 mile-long, 2.5 mile-wide demilitarized zone between the two countries. Although there are heavy fortifications on both sides of the DMZ, there's very little in the middle. The Korean DMZ eventually gains fame as some of the most unspoiled temperate wildlife habitat in the world (at right).
July 27, 2010: In the wake of the Deepwater Horizon oil spill, BP announces CEO Tony Hayward will leave the company on Oct. 1.
Photo: Wikimedia Commons