A mysterious circle appeared in the sky over the Hudson River recently. Some thought it was birds, others unidentified areal phenomenon, but they were wrong.

Images were plastered all over Facebook, showing the strange anomaly floating ominously over northern Dutchess County near Poughkeepsie, New York. The black circle reportedly hung in the air for quite a while, making many who saw it uneasy.

Some made incorrect assumptions

After photos and video of the ring was released, many Facebook experts claimed that it was a "murmuration of starlings.' These migratory birds have been known to fly in some amazing patterns, somehow working as a team to put on a spectacular show.

While this may explain a temporary circle in the cloud, it's not possible that the birds would hold that tight pattern for longer than a second or two before transforming into another shape.

YouTube/sopfoknie

So if it wasn't birds, what was it?

Social media in the Hudson Valley users were boggled by this strange circular pattern in the sky until some pointed out that it could have been a result of a nearby air show. While fast-moving planes have been known to transform cloud patterns, the old biplanes used in local airshows aren't quite fast enough to make a giant ring like the one seen over Rhinebeck.

The mystery was finally solved after footage was released from the Old Rhinebeck Aerodome. It turns out that the ring is a result of the airshow, but not from any of the actual airplanes. At the end of the show, which was scheduled on Sunday afternoon from 1pm to 4pm, a giant explosion is set off as a part of the storyline. The villain in the World War 1 show is made to look like he's been blown up. The effect is made by setting off a loud explosion that mushrooms into a black cloud.

YouTube/sopfoknie

If the air is still enough, the cloud will eventually form a smoke ring that can travel great distances around the Hudson Valley area. Apparently, weather conditions on Sunday were ideal for the effect to linger longer than usual.

While that solves the Hudson Valley black ring, there are still other unexplained circles seen in the skies all over the world. Scroll below to see some of the more spectacular rings captured on film.

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