The first graph is from Doug Short of dshort.com (financial planner): "Four Bad Bears".
This is the 2nd worst S&P 500 / DOW bear market in the U.S. in 100 years.
Note that the Great Depression crash is based on the DOW; the three others are for the S&P 500.
See Doug's: "The Mega-Bear Quartet and L-Shaped Recoveries".