What city did both Muddy Waters and Mel London live and work in together? 
Chicago
Title: Mel London
Passage: Mel London (April 9, 1932 – May 16, 1975) was a songwriter, record producer, and record label owner.  He was active in the Chicago blues and R&B scenes in the 1950s and 1960s.  London is best known for his compositions for Chicago blues artists Howlin' Wolf, Muddy Waters, Elmore James, and Junior Wells as well as being the record producer and owner of Chief Records (and its Profile Records and Age Records subsidiaries).
Title: The London Muddy Waters Sessions
Passage: The London Muddy Waters Sessions is a studio album by Muddy Waters, released in 1972 on Chess Records.  A follow-up to 1971's "The London Howlin' Wolf Sessions," the concept was to combine American bluesmen with British blues/rock stars.  The album was an attempt to capitalize on the British rediscovering of traditional blues music and blues artists.
Title: Muddy Waters
Passage: McKinley Morganfield (April 4, 1913April 30, 1983), better known as Muddy Waters, was an American blues musician who is often cited as the "father of modern Chicago blues".
Muddy Waters Mel London