my husband and I were on holiday in crete, Greece, and as amateur astronomers, would often lay on sunbeds at night on the roof, and just be.4 days into our holiday, and with our eyes adapted for at least half an hour, I glanced a shape moving aross the sky, just above one or two tiny puffs of white cloud. other than that the sky was clear.I said to my husband "what the hell is that?" and he saw clearly, along with myself, a grey, flat or dull surfaced chevron shape.the leading edge was wide and flat, as if the point of the craft had been cut off. there was a triangular "nick" in the rear end.there was a dark line around the whole edge, and 3 lines on each side at the rear.it was big, completely silent, and with no lights whatsoever. it moved gracefully and in a straight line.we watched transfixed as it went over for around 30 seconds until we lost sight of it over the white mountains.we tried to rationalise it.. the usual suspects, but we couldn't. we felt slightly disturbed for a few days afterwards, and I can still see it fresh in my mind to this day. my husband was shocked, as it was the first time he has seen a UFO,but as my third sighting, I was a little more accepting.we carried on looking each night, but alas saw nothing else of note.