Heritage Open Day: The Guildhall is the only Grade I listed building in the old town of Harwich, Essex. Historic Grade I Listed building. Originally the Bear Inn, it was bought in 1673, rebuilt in 1769 and converted into a Guildhall and Gaol. House Regalia dates back to 1605 and the old gaol, on the ground floor, has wall carvings of ships by French prisoners, dating back to the late 1700s. See the Council Chamber and former Magistrates Court on the first floor as well as the Mayor's Parlour.