This is the Photo of a purported UFO over New Hampshire in 1870; known as the mystery airship.
The popular name for them is "flying saucers". Studies of the saucer report show that UFO's are ver different from one another. Some people report they have seen flat saucers; and the others saucers shaped like spheres, cigars or doughnuts. The colours of saucers seem to be different as their sizes. Some seem to change colour as they are being watched.Saucers have been seen to move in every direction and varying speeds. They move straight up or down, turn at right angles, or travel in a zigzag path. They can hang motionless in the air, and make either a hissing noise or a roar. When the investigation was undertaken by the United States Air Force of the flying saucers report,it discovered that people weren't "imaging" what they saw. Everyone who reported a flying saucer had seen something. But what? It may be a weather ballon, a satellite, a cloud, a meteor, a star, a bird, a comet, a planet, or fireworks. It was also called as sun dogs. They are images of the sun reflected through ice crystals. If saucers were really spaceships, there would be a certain pattern in the reports about them. But there is no such pattern. So scientists believe that there is no evidence that we are being visited, watched, or invaded by intelligent beings from other worlds