Undefeated heavyweight contender Anthony Joshua has 15 knockouts sa kanyang 15 propesyonal fights. Check out this video compilation from SHOWTIME Sports showcasing all of Joshua’s KOs. And tune in ito Sabado to watch the 2012 British Olympic Gold Medalist challenge undefeated American titlist Charles Martin for the IBF Heavyweight World Championship, nang live sa showtime sa 5 p.m. AT/2 p.m. PT from The O2 in London.