A show looking behind the scenes at Lancaster Castle is airing on Netflix as part of two seasons of Secrets of Great British Castles.
In Season Two, presenter Dan Jones explores the turbulent military, political and social histories of several castles including our very own.
One of Britain's oldest citadels, Lancaster Castle remains infamous for its long record of religious persecution, witch trials and grim executions, and Dan Jones finds out some of the surprising history behind the legendary castle.
It is believed Lancaster Castle may have been founded in the 11th century on the site of a Roman fort overlooking a crossing of the River Lune.
In 1164, the Honour of Lancaster, including the castle, came under royal control. In 1322 and 1389 the Scots invaded England, progressing as far as Lancaster and damaging the castle. It was not to see military action again until the English Civil War.
The castle was first used as a prison in 1196, although this aspect became more important during the English Civil War.
The castle buildings are owned by the British sovereign as Duke of Lancaster, and part of the structure has been used for many years to host sittings of the crown court.
Until 2011 the majority of the buildings were leased to the Ministry of Justice as HMP Lancaster, after which the castle was returned to the Duchy's ownership.
The castle is now open to the public seven days a week and has undergone a large-scale refurbishment to include a new public piazza and cafe, as well as being used for events such as Lancaster Music Festival.
Season One of Secrets of Great British Castles looks behind the scenes at Dover Castle, The Tower of London, Warwick Castle, Caernarfon Castle, Stirling Castle and Carrickfergus Castle.
And in Season Two, you can find out all about Edinburgh Castle, Cardiff Castle, York Castle, Leeds Castle in Kent and Arundel Castle, as well as Lancaster.