The Belgian UFO wave

From November 1989, starting near Eupen, people in Belgium reported large triangular objects flying low and silent, in a wave of sightings that ran until 1991.

Wim Van Utrecht, writing for Caelestia, starts with two gendarmes from Eupen on 29 November 1989. Driving their patrol car toward Kettenis at around 5:20 p.m., they saw a bright light above a field beside the road that seemed to be travelling alongside them. They drove to where they expected it to pass overhead, but as it came near it stopped, turned around and went back the way it had come.

Skeptoid's Brian Dunning says the gendarmes described a large, silent triangle at low altitude with a bright light at each corner, and that 143 people in all reported seeing it, in thirty groups of witnesses plus three groups of gendarmes. Wikipedia gives the same total of 143 and notes that most of the reports came in more than a week after the event and after it had been in the news.

The best-known picture from the wave was taken at Petit-Rechain and shows a black triangle lit at its corners and centre. In 2011 its maker admitted it was a fake. He told Reuters, as The Week reports, that they built a polystyrene model, painted it, added details, hung it in the air and photographed it. Le Figaro noted at the time that believers had held up the photo as proof that the sightings of 1989 to 1991 were more than psychosocial contagion. The confession concerned that photograph alone.