I Was at the front yard of my house. I was just relaxing after sun set, 7:12 P.M. I saw the sky at west looking for venus and jupiter that lying there on this month, then I look the sky in north direction between my house and the neighbour's house when i saw in the sky a dark and solid flying object with spherical shape passing in SE direction over my neigbourhood and then fade away over the "Jard��n Bot��nico Nacional" 3 mile away from downtown Santo Domingo, Dominican Republic. I thought that I needed whitnesses and I called my wife and children and I showed them the flying oject. At the first time I thought it was an air balloon, but I realize that this object isn't a air balloon or any other known aircraft because the object looked solid or metalic. The aircraft was an sphere between 6 to 8 meters in diameter, black color with soft shades of gray and with a solid texture. The sustained and straight way in which the aircraft flew is not typical for air balloons. The speed was aproximately 300 km/hour. The aircraft don't have propellers, external engines, windows and basket like a air or helium ballon.The flight was silent and without scape gases and without navigation lights.The height of flight was about 500 feet and was constant during all event. I feel shocked bacause this sighting was rare and possibly an UFO experience. I never before had had an UFO experience.I never before had believed in UFO or extraterrestial intelligence. I'm civil engineer with master degree. I am a professional trained in mathematical and physical sciencies. My job is estimating distances, meansures, volume, areas, etc. I do all kind of observations to appreciate and solve physical problems with mathematical models. I am not easily impressed for all I see. We were completely sober at the time of the sighting and we are people that not need the media attention or any other thing. I dont took photos because the camera wasn't ready at the time of facts. A half hour after the sighting I called to Operations Center of "Aeropuerto Internacional de Las Americas" 19 miles from Santo Domingo to report the event. They took note of my phone number and name, but they hasn't called to me back. I called to radio station Z101 to report event too. I lose sight of the object like any other aircraft that fade away and losses as a point in the distance.