A Listed Building or structure is one that has been put on a statutory list of buildings of special architectural or historic interest. Historic England maintain the list. You can search the list of historic buildings at http://historicengland.org.uk/listing/the-list/results?searchtype=nhle&page=3 Buildings can be listed individually or in a group. Most listed structures are buildings but bridges, monuments, sculptures, war memorials and even milestones can be listed. Ancient uninhabited structures, such as Strickland’s Pele Tower or Beacon Tower are sometimes classified as scheduled ancient monuments.
There are three types of listed buildings in England and Wales:
Grade I – buildings of exceptional interest
Grade II* – particularly important buildings of more than special interest
Grade II – buildings of special interest warrenting every effort to preserve them.
Penrith has a number of Listed Buildings which can be found by clicking on the link.