Yale University Professor Irving Fisher declared the “Dow Jones Industrial Average had reached what looks like a permanently high plateau.”
8 days later Dow drops 2%
Black Monday; October 28, 1929 Dow drops 13%
October 29, 1929 Dow drops 12%
Over the next 3 years the Dow drops 89%.
July 1932 Dow Jones Industrial Average is at its lowest point.
The Dow did not regain its October 16, 1929 peak until November 1954.
Took 25 years to recover 3 years of losses.
Source: The Ascent of Money by Nial Ferguson