http://www.bbc.co.uk/norfolk/funstuf..._ring_01.shtml
Lord of the loops - the perfect circle
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.
