Any unexplained object that people see in the sky is known as an Unidentified Flying Object, or UFO. Today, one in seven Americans claims to have seen a UFO. Learn more in Investigating UFOs, a World's Greatest Mysteries book. Read More
Any unexplained object that people see in the sky is known as an Unidentified Flying Object, or UFO. Today, one in seven Americans claims to have seen a UFO. Learn more in Investigating UFOs, a World's Greatest Mysteries book. Read Less
