A clear and sunny day in a small city in the country. Important to say there was a small airport w/ small planes.No big planes flying over the place (it wasn't a route) and jet planes weren't flying in Brazil by that time. I went out the house, located on a high place) and something in the sky captured my attention: a shine. when I looked at the sky there was that big "cigar" flying very very fast and the sundown light was causing the shine in one of its "tips". It had no wings or other visible details. It appeared to be in metal, plumb color but "polished". Totally soundless. Based on my experience with planes, I can estimate it was about 3,000 meters high (1,800 feet)and the speed was 4/5 times more than a jet plane (3,000 to 4,000 km/hour) or more. It came from East crossing the sky and disappeared going to the West. At the distance I saw it, I can say it's size was very similar to a Boing 707. It was such a surprise to see that and it was so fast, I don't remember thinking something special. Only when it desappeared I went in the house and told to the family what I saw. I was 17 years old and of course the fact had impact on me, but positive. Since that time I use to read about.