Legendary Essex Note: 

Colchester Castle was built on the foundations of a Roman Temple of Claudius, which was the first Roman capital of Britain. The keep of the castle is mostly intact and is the largest example of its kind anywhere in Europe.
In 1645, Matthew Hopkins, the self-proclaimed Witchfinder General, used the castle to interrogate and imprison suspected witches
During the English Civil War, Royalist leaders Sir Charles Lucas and Sir George Lisle were executed on the castle ground – Legend has it that grass refuses to grow where their heads fell.
There are too many hauntings and ghost stories in the and around the castle to mention here, but they are written about brilliantly at the Castle website.