Our press, radio, television almost every day report on flights of “flying saucers”, UFO landings on various territories of the globe, and meetings with aliens. People's interest in these phenomena is enormous. And although many, at first glance, incomprehensible phenomena can in one way or another be explained by completely natural causes (optical phenomena associated with solar radiation, flights of out-of-control balloons, atmospheric pollution by industrial emissions, etc.), the nature of UFOs is completely remains unclear. There is a lot of mystery in our past; religion is full of contradictions. Scientists have failed to find convincing evidence of the natural origin of life on Earth. Numerous finds of recent archaeologists do not agree with either traditional science or our usual ideas about the world around us. The author of the book does not try to somehow explain this or that unusual phenomenon or incident. He only summarized known facts scattered across various sources. The reader will draw conclusions about the origin of UFOs and the possibility of the existence of aliens.