What happened
On the evening of November 29, 1989, two gendarmes from Eupen, Heinrich Nicoll and Hubert von Montigny, saw a large, flat, triangular object with three bright lights and a red light in the middle moving slowly and silently over the fields. That same night, dozens of other people filed similar reports. Over the following months, the Belgian association SOBEPS recorded thousands of accounts, several hundred of which were investigated in detail. On the night of March 30–31, 1990, after reports from the ground and returns on ground radars, two F-16 fighters took off from Beauvechain Air Base, and their radars repeatedly locked onto targets that abruptly changed speed and altitude. The Belgian Air Force openly cooperated with civilian researchers.
Witnesses
Gendarmes Heinrich Nicoll and Hubert von Montigny, thousands of residents of Belgium, and Belgian Air Force pilots and radar operators.
Explanations and hypotheses
The Belgian Air Force did not explain the wave, and the head of its operations section, Wilfried De Brouwer, admitted that the military had been unable to identify the objects. The radar returns of March 30 are now attributed mainly to interference and temperature inversion, and some of the sightings to aircraft, stars, and helicopters. The famous photograph of a triangle from Petit-Rechain, taken in April 1990, turned out to be a hoax – its author admitted in 2011 that he had photographed a Styrofoam model.
Disputed A likely explanation exists, but some of the facts are still disputed.
More: Wikipedia (en)