Two Japanese sumo wrestlers posed with referee by Felice Beato and Baron Raimund von Stillfried https://www.rawpixel.com/image/14263002/photo-image-dog-face-personFree Image from public domain license[Untitled photo shows: Henry Armstrong, boxing champion, with his opponent Lew Jenkins and referee Arthur Donovan at the… https://www.rawpixel.com/image/12299455/image-person-man-jewelryFree Image from public domain licenseReferee, American football game, stadium. Original public domain image from Flickr https://www.rawpixel.com/image/8731929/photo-image-public-domain-peopleFree Image from public domain licenseFree american football referee during game photo, public domain sport CC0 image. https://www.rawpixel.com/image/5919660/photo-image-public-domain-free-gameFree Image from public domain licenseManhattan Beach Coast Guard training station. Lou Ambers, former world's lightweight champion, sparring with Marty Servo… https://www.rawpixel.com/image/12306711/image-person-beach-footballFree Image from public domain licenseIn what seemed to be the most anticipated fight of the night, U.S. Marine Cpl. Jamel Herring dodges a punch thrown by U.S.… https://www.rawpixel.com/image/8738974/photo-image-public-domain-sportsFree Image from public domain licensePlayers meet for a coin toss prior to the start of the U.S. Air Force Academy's opening football game against the Idaho… https://www.rawpixel.com/image/8738862/photo-image-public-domain-sportsFree Image from public domain licenseU.S. Marines and British Royal Marines compete in a boxing match during the Royal Marines Sports Association Tour at Barber… https://www.rawpixel.com/image/8738652/photo-image-public-domain-sportsFree Image from public domain licenseAmerican football players on field, Texas, The United States, 13 August 2016. View public domain image source here https://www.rawpixel.com/image/6113259/photo-image-public-domain-people-freeFree Image from public domain licenseAmerican football referee first down signal during game, location down, May 22, 2016. View public domain image source here https://www.rawpixel.com/image/6111536/photo-image-public-domain-people-freeFree Image from public domain licenseCloseup on ice hockey referee, location unknown, 13 March 2016. View public domain image source here https://www.rawpixel.com/image/6113906/photo-image-public-domain-people-iceFree Image from public domain license15BSB Football GameA football game consisting of Soldiers from 15th BSB. Original public domain image from Flickr https://www.rawpixel.com/image/4040386/photo-image-public-domain-people-menFree Image from public domain license