You can get the history of the Dow pretty easily, along with other stock indexes and individual stocks. A lot of sites will do it, but I usually turn to Yahoo Finance for stock market history. The Dow closed at $241.70 on December 2, 1929. The closing price on June 30, 1930 was 226.34. It would be another two years before the Dow hit its all time low of $41.62 on July 5, 1932.
Need more information? Newspaper archives are one of the best online research tools.