A mystery ring which appeared in the Norfolk sky on Monday 1 March has been explained by air traffic control at Norwich Airport.
A US military pilot carrying out an air test at 35,000 feet - about six and a half miles high - flew a perfect circle above Dereham.
The weather conditions meant he left a vapour trail which could be seen from as far away as Norwich.
People from across the county have sent in their photos of loop in one of our most popular photo galleries ever. Thanks to everyone who sent in their snaps.
This photo was sent in by the Norwich Operations Unit for Bristow Helicopters.
The team joked it was a smoke ring from a woodbine.
John Rumball sent this photo of the vapour ring over some rooftops.
Who would believe the loop was six and a half miles up!
This was the view of the circle above Brooke, near Bungay, which was snapped by Barrie Russell.
Benjo Giller took this picture through some trees at Maypole Green, Toft Monks.
