June 24th, 1947, Kenneth Arnold, an experienced pilot, was flying his CallAir A-2 over the beautiful Cascade Mountains in Washington searching for a downed Marine transport plane.
As Arnold was flying, a bright reflection caught his eye. For several minutes he observed what he termed to be nine very large peculiar-looking aircraft flying from north to south, in formation, with tremendous speed through the crystal-clear sky ahead of him. As a pilot, the sight was extremely intriguing because they were flying so low over the mountaintops, appeared to be crescent or boomerang-shaped, skipped like a saucer, and most curiously, had no tails.
Witnesses on the ground, and other pilots in the air, concurred with his sighting of these mysterious disks, I saw them and I know they are real. Yet, no explanation has ever come forth.
This was noted as the very first major UFO sighting in the U.S. Using his description, the term flying saucer was born.