Today marks the final day of the 2012 New Orleans Jazz and Heritage Festival. Officially this is the 43rd annual Jazz Fest in the Crescent City, but a close look at history shows that the inaugural festival in in 1970 in Congo Square (across North Rampart Street from the French Quarter) followed years of earlier efforts to stage such an event The earliest jazz festivals in New Orleans grew out of the work of the New Orleans Jazz Club, founded in 1948 after its short-lived predecessor, the National Jazz Foundation, folded. The NOJC held a small jazz festival of sorts with several concerts in Congo Square in 1949 and 1950. After a promising start, a series of unfortunate events in the 1950s and 1960s…