Well not today, it was the 19th but that's the closest Monday. Anyway, it was a Monday (a day like any other day) when the Dow fell 22.6% in a single day. That was only 508 points at the time (what inflation?) and it dropped to from 2,246 to 1,738. That happened pretty close to the anniversary of the original Black Monday of October 28th, 1929, which kicked off the great market crash and the Great Depression.