Michael Phelps won 23 gold medals over four Olympic Games. Lee Jin-man / AP Photo
Michael Phelps won 23 gold medals over four Olympic Games. Lee Jin-man / AP Photo
Michael Phelps challenges Conor McGregor to swimming race: 'I'll give him a 50m head start'
American Olympic great is in Dubai for the opening of the Under Armour store in Dubai Mall.
