Why is LaSalle Street in Chicago important?

There could be many answers to this question as many people, businesses, and organizations call LaSalle Street their home and various historical events have transpired on and around LaSalle Street in Chicago. A notable usage of LaSalle Street was in the filming of Batman: The Dark Knight and Ferris Bueller's Day Off. LaSalle Street is home to the Chicago Board of Trade building which is a center of commerce and finance for the city of Chicago and the international financial markets.