Organisers of a battle re-enactment event have provided pictures showing how the mystery smoke screen above the M62 was formed.
The weird phenomenon was captured on film by Kimberley Robinson and her boyfriend Danny Cooper, of Bury, over the M62 near Birkenshaw last Sunday.
The circle of black smoke puzzled Examiner readers – with some even suggesting it was proof of UFO activity.
However, organisers of The Yorkshire Wartime Experience, a two-day wartime re-enactment event, dispelled all debate by admitting that the smoke ring had been created by pyrotechnics experts creating mock explosions on the battlefield.
And they have shared a number of pictures showing the smoke rings being formed as tanks and armoured vehicles took part in the annual event which is held annually at Hunsworth Lane, Hunsworth, near Cleckheaton.
Sarah Clarke, one of the organisers, said: “The reason the smoke ring drew such interest is because there was little to no breeze, causing the ring to float across the sky instead of dispersing quickly.”
Sarah said: “We will be back next year – July 6 to 8 – and have over 400 military vehicles, WW1, WW2 and post war displays, battle re-enactments and lots of stalls and entertainment.”