I think this is a very interesting graph.
Here is the output of The Bubble Index of the Dow Jones Industrial Average with a 10,080 day window. Note the peak in late 1960’s and the peak in late 2007. NOTE: Value of 100 corresponds to the maximum level of the index, reached on November 16, 2007. Also, I have included a similar graph of the S&P 500 located below.