It was winter and I was with my mom and dad at our grandparents house.It was already dark outside and I was staring out the window, watching the fields behind their home and the city lights on the horizon.All of a sudden I saw an object hovering behind one of neighbours' trees. The tree is approximately 4 meters (about 12 feet I guess) away from the window and about 4-5 meters high (ca. 12-15 feet), but the object appeared much farther away (The object seemed to be about 300-500 meters away). Still the object was at tree level, so must have been hovering pretty close the ground.At first I only saw three lights, positioned in a triangle shape. They were red, blue and green and they changed colours in a random way, but there were never two lights which had the same colour at any given time. So at first I thought it was the reflection of something in the house (like those small 'party lights' you can buy at the kids store), but when I looked behind me I couldn't see anything projecting such lights.I looked outside again and I couldn't really figure out the shape of the object, but because we live in an area that has a lot of light pollution (which makes the sky look brighter), I could now at least tell that it was an object and not just lights, because I saw a silhouet that appeared darker than the nightsky.It hovered a little longer and all of a sudden it flew away at an amazingly fast speed, right into the sky and disappeared.I the whole event took about 2-3 minutes.I was kind of intrigued at first and kept staring outside to see if I could spot it again. When I couldn't find it, I asked my family, who were standing a bit further away, if they saw it too, but they didn't...I didn't really bring it up ever again, but besides from the exact date (because it has been 7 years) I remember the experience quite vividly, which I find a bit strange.