• A look at sports stars who retired early

    FILE  - In this April 27, 1956 file photo, World heavyweight champion Rocky Marciano gestures at a new conference in New York after announcing his retirement from boxing. Marciano had been the world heavyweight champion for four years and won all 49 of his fights _ 43 by knockout _ when he retired in 1956 at the age of 32. The American wanted to spend more time with his family. (AP Photo, File)

    LONDON (AP) — Nico Rosberg stunned the world of Formula One and beyond by announcing his retirement on Friday at the age of 31, five days after winning his first drivers’ championship.