View Photo Gallery: A look back at the boxer’s life and career.

Muhammad Ali turns 70 today and the world stops to notice — just as it always has for him — and wish him well.

Cus shared his birthday with the greatest, Muhammad Ali. Happy 70th. I remember you visiting at Spofford & wanting to be like you.Tue Jan 17 16:24:50 via Twitter for iPhoneMike Tyson

A big Happy 70th Birthday to Muhammad Ali! Jan 17 17:25:26 via HootSuiteKareem Abdul-Jabbar

Happy Birthday to a friend & one of the greatest athletes in history, Muhammad Ali.Tue Jan 17 18:01:09 via WhoSayEarvin Magic Johnson

HAPPY 70TH BIRTHDAY GOAT!!! MUHAMMAD ALI We luv u champ..Tue Jan 17 17:51:25 via Twitter for AndroidBERNARD HOPKINS EX

Happy 70th bday to Muhammad Ali. You perfected the art of trash talk & backed it up...Tue Jan 17 16:13:43 via TwitterrificLogan Morrison

Happy Birthday Muhammad Ali! RT!Tue Jan 17 19:33:20 via HootSuiteNick Cannon

Happy Birthday Muhammad Ali Truly the greatest and a great inspiration to us as athletes and men. “Rumble Young Man Rumble”..Tue Jan 17 18:29:52 via webTracy McGrady