What happened
On September 4, 1971, at 8:25 a.m., an aircraft of Costa Rica’s National Geographic Institute was taking aerial photographs for the state electricity institute, which was preparing a project around Lake Arenal. The crew – Sergio Loaiza, Juan Bravo, and Francisco Reyes – photographed the terrain with a camera mounted in the floor of the aircraft, which took a picture every dozen or so seconds. One frame, over Lake Cote, shows a distinct, disc-shaped object with a metallic sheen; there is no trace of it in the adjacent frames. None of the crew noticed anything during the flight – the object was spotted only when the material was being processed. The photograph was published in the press and for years was considered one of the best UFO photographs in the world.
Witnesses
The crew of the National Geographic Institute aircraft – Sergio Loaiza, Juan Bravo, and Francisco Reyes – who, however, saw nothing during the flight.
Explanations and hypotheses
Richard Haines and Jacques Vallée, who analyzed the photograph in the late 1980s, concluded that the oval shape was more likely an artifact – such as a pressure mark on the film – than an image of a physical object, while noting that they did not have access to the original negative. Others point to a bird or a reflection. The photograph is still analyzed from time to time, but no analysis has been conclusive.
Disputed A likely explanation exists, but some of the facts are still disputed.