President Obama, boxer Floyd Mayweather, Olympian and reality show personality Caitlyn Jenner, musical artists Sean "Diddy" Combs and Paul McCartney and former President Bill Clinton are among the many notables mourning boxing great Muhammad Ali via social media.
"Today my heart goes out to a pioneer, a true legend, and a hero by all means!" Mayweather posted via Instagram and Twitter. "Not a day went by entering the gym that I didn't think of you. Your charisma, your charm and above all, your class are all of the elements that will be greatly missed by myself and the world. You are someone that inspired me greatly throughout my boxing journey and words cannot express how great you were as a person! Thank you for everything you've done for Black America, in the the world of sports & entertainment and for the legacy you leave behind! My sincerest condolences to the Ali family!"
WSB posted this great photo: