Manny Pacquiao of the Philippines takes a punch from Floyd Mayweather, Jr. of the US (R) in the fourth round during their welterweight WBO, WBC and WBA (Super) title fight in Las Vegas, Nevada, May 2, 2015. Floyd Mayweather remained undefeated after 12 rounds in the richest fight in boxing history – a bout that made Mayweather at least $180 million. [Photo/Agencies]