Which country has the best military record in history?
It depends. Most countries have been around so long their military record is bad because they get losses eventually. Mongolia has a very good military record, Ghengis Khan in the middle ages was the most feared warrior and im honestly not sure if he ever lost a battle. He conquered the most territory an empire has ever conquered. Rome had a good military record until late antiquity, where the barbarians started overrunning them. The modern US has only lost one war which was Vietnam, although they didn’t gain as much territory as the 2 above empires. Every country has famous generals too, no single country out there has been a dominant in military for a long time. There has always been someone better and stronger eventually.