 "Conversation Peace" and the live album "Natural Wonder" were released in the 1990s.Among his other activities he played harmonica on one track for the 1994 tribute album ""; sang at the 1996 Summer Olympics closing ceremony; collaborated in 1997 with Babyface on "How Come, How Long", a song about domestic violence that was nominated for a Grammy award; and played harmonica on Sting's 1999 "Brand New Day".In December 1999, Wonder announced that he was interested in pursuing an intraocular retinal prosthesis to partially restore his sight.