Metal grinding sound effect was what we had as an airborne sound transmission. When i say, we , i am referrring to we, inhabbitants of the Mineiro Triangle a region involving the towns of Uberaba, Uberlândia e Patos de Minas. The sound produced in Uberlândia had the same characteristics as the sound which rumbled in Patos. A metal grinding sound effect that scared the ignorant populace. The so called narrow minded media showed up with weird fake explanations which did not appeace the most critic minds. But i know now it became new trends denying everything and poking ridicule on such commentaries. Something very weird seems to be going on. And since we still do not know what is really going on we will tend to atribute these reports as the product of a fertile imagination.