<human>:  Did Cynthia Powell celebrate a silver anniversary with John Lennon?
<bot>: No, Cynthia Powell did not celebrate a silver anniversary with John Lennon. A silver anniversary takes place during the 25th year of marriage. Cynthia Powell married John Lennon in 1962. Cynthia Powell and John Lennon got divorced in 1968, so Cynthia Powell did not celebrate a silver anniversary with John Lennon.