Which NBA player has the most championships in NBA history?

Context: William Felton "Bill" Russell was an American professional basketball player who played as a center for the Boston Celtics of the National Basketball Association from 1956 to 1969. A five-time NBA Most Valuable Player and a 12-time NBA All-Star, he was the centerpiece of the Celtics dynasty that won 11 NBA championships during his 13-year career.

Answer: William Felton "Bill" Russell won 11 NBA championships during his 13-year career with the Boston Celtics.