The Metric System was defined so that the distance from equator to pole should be exactly 10 million meters or 10,000 kilometers. It isn't exactly, because the model for the shape of the earth in those days wasn't perfectly accurate, but it's quite close. So all UTM grid systems, NATO or Warsaw Pact, begin counting from zero at the equator. Thus it is possible to create numbering systems so that distances on the grid in kilometers have at most three digits. Like so many things in cartography, the UTM system was inspired by the military.
Some scientists object to using it for that reason.
My philosophy is that if you refuse to use a useful tool because of its origins, you probably have other problems that will keep you from being an effective scientist. Maps in the U.S., Canada, and many western European countries use a grid system common to NATO, the North Atlantic Treaty Organization. The map above shows how the NATO UTM system divides the earth into 60 longitude zones, each six degrees wide. The numbering begins at Zone 1 at 180 degrees west and proceeds eastward. Divide by 6 and round up to the next higher number.