During a summer night, sitting with my wife in our backyard, looking at the stars, we saw a small luminous sphere approaching to us. The colour was a very beatiful pure emerald green. Size about 1 feet diameter, but difficult to estimate exact size. It flew slowly (about 6 miles/hour) in an horizontal path, with a zig zag movement with no sound, seemed to move just above the trees, about 45 feet tall. It seemed to be searching for something. It took us less than two seconds to realize that was something very weird, I had a knot in my throat and hardly could say: “what the h… is that!”. After a few seconds I rushed inside the house to get my camera but when looked at the sky again it has vanished. Since that day my wife never wanted to talk about that anymore. More than 20 years later, it gives me goosebumps just recalling the sighting. After that I kept on reading about that kind of sightings, now I know what I saw was a “foo fighter”.