Question: Kozmic Blues was performed by Janis Joplin as part of which iconic festival set?
Related documents: [0]  [DOC] Janis Lyn Joplin ( ; January 19, 1943 – October 4, 1970) was an American rock singer and songwriter. She was one of the biggest female rock stars of her era. After releasing three albums, she died of a heroin overdose at age 27. A fourth album, "Pearl", was released in January 1971, just over three months after her death. It reached number one on the "Billboard" charts. [END] 
[1]  [DOC] "Kozmic Blues" is a song from Janis Joplin's "I Got Dem Ol' Kozmic Blues Again Mama!" album, her first after departing Big Brother and the Holding Company. It was a part of Joplin's set at Woodstock Festival in 1969. Although the concert as a whole is not regarded as Joplin at her best, that specific performance became very popular and was released on "The Essential Janis Joplin". [END] 
Answer: 
Woodstock
Woodstock