Underneath St Kyneburgha's Church, Castor are the remains of one of the biggest buildings in Roman Britain. Parts of its walls still can be seen in various parts of the village. The site has been explored over several hundred years with early antiquaries confused by what the mosaic floors and several bath houses all meant. We now know that the site was probably part of a vast Imperial Estate from where much of the fenlands was governed. The building appears to have been the administrative centre of this estate and was where a procurator would have held court and possibly lived. The building on the top of the rise, where the church now stands, would have been seen for miles as a symbol of Roman power and authority.