Everyyear,overathousandclimberstrytoreachthesummitofMountEverest,withtheannualrecordforsuccessfulattemptscurrentlystandingat633.Butofthatnumber,nearlyhalfwereSherpas-themountain"sunsungheroes.YettheSherpacommunityhasremainedsecretiveabouttheirnation,cultureandexperienceslivingintheshadowoftheworld"s...