Does the Zone of Silence exist at all, even with respect to the mildest of claims? Neither I nor anyone with whom I spoke (apart from the zoneros) had any trouble with either their radios or compasses while working in the Reserve. The claims of mutations refer to natural phenomena; the triangles are a normal pattern variant in the Bolson tortoise populations and the pads of nopal coyotillo turn a shade of violet during a dry spell. In addition, the human population is made up of all sizes and types, just like any of the surrounding populations. However, the only local person most of the zoneros have seen either in the Reserve or in Gomez-Palacio is the resident of the Reserve’s field station, who indeed is bigger than most. Yet they do not seem to notice that many of his cousins or brothers do not come up to his shoulders, even with their hats on.
As to the Zone itself, there seems to be little consensus on exactly where it is. It was originally considered to be the place where the missile fell. This is also the place marked on the topographic maps of INEGI and the road maps of American Automobile Association. Sometime in the last twenty years, the spot moved to closer to the preson of El Tapado, where an engineer working for PEMEX claimed his equipment stopped functioning. Since then, the exact spot has marched its way north, and the hapless visitors may be guided to any number of areas in the Reserve. Most guides take their customers to an area where they can collect fossils near the preson of El Macho, or further south, to an area which is littered with the little smooth pebbles that look like meteorite debris. In addition, the local residents find the zoneros a nuisance and tend to get them to move on by indicating that the zone is just a little further down the road. Upon being asked where la Zona could be found, a local rancher told a carload of people that they needed to keep following the road until they saw martians jump from one side of the road to another. The amazing part, he commented later, was that they thanked him. Another group of zoneros arrived at the field station and asked one of the workers how to get to the Zone. The young fellow, struggling to be polite and truthful at once, only replied, “Nunca van a llegar (You are never going to get there).” [http://www.mexconnect.com/articles/1468-the-zone-of-silence-of-nothern-mexico-scientific-marvel-or-just-fiction]