Oscar Natalio "Ringo" Bonavena (September 25, 1942 – May 22, 1976) was an Argentine heavyweight professional boxer with a career record of 58 wins, 9 losses and 1 draw.

[2] Bonavena began his early career in New York City under the management of World War II hero and dentist Marvin Goldberg.

[4][5] Bonavena first came to wide public attention after a fine performance: defeating rated contender and Canadian champion George Chuvalo, boxing technically better than expected, and later going the distance against the young hard-hitting great Joe Frazier.

[citation needed] In 1967, after the World Boxing Association stripped Muhammad Ali of the title for refusing to be inducted into the U.S. military, Bonavena participated in that sanctioning body's 1967 tournament to crown a new heavyweight champion.

In a strong performance he decked favoured European champion Karl Mildenberger four times,[6] winning by a decision in Frankfurt, West Germany.

[8][9] After the loss to Ali in 1970, he had a brutally tough match with underrated Alvin Lewis, being decked multiple times but eventually winning by disqualification.

[citation needed] Eventually losses to Floyd Patterson in 1972 and Ron Lyle in 1974 effectively relegated him to lower contender status, though he did well enough in both matches.

[11] On 22 May 1976 Bonavena was shot dead at the age of 33 by security guard Willard Ross Brymer at the Mustang Ranch brothel near Reno, Nevada, after having become involved in a conflict with its owner, Joe Conforte.

[11][12][13] His body was returned to Argentina to lie in state at the Luna Park sports arena in Buenos Aires, where 150,000 people filed by.