Just a guess.
Black Monday (1987)
Black Monday refers to Monday, October 19, 1987, when stock markets around the world crashed, shedding a huge value in a very short time. The crash began in Hong Kong and spread west to Europe, hitting the United States after other markets had already declined by a significant margin. The Dow Jones Industrial Average (DJIA) fell exactly 508 points to 1,738.74 (22.61%).[1] In Australia and New Zealand, the 1987 crash is also referred to as "Black Tuesday" because of the time zone difference.