Secrets of Great British Castles

Popular historian Dan Jones visits the south east of England, home to Britain's greatest defensive fortress: Dover Castle.

This time, Dan Jones is exploring one of the oldest, and most fearsome, castles ever built: the Tower of London.

Dan Jones is in the heart of the English countryside at Warwick Castle, which may appear idyllic today, but for centuries Earls of Warwick, the owners of probably Britain's most lavish castle, inherited a poisoned chalice as some suffered financial ruin and even murder.

Historian Dan Jones is in the heart of Snowdonia, exploring a stronghold built not only as an impenetrable fortress, but as a lavish royal palace fit for a fairytale - Caernarfon Castle.

Dan Jones travels north to one of the most strategically important castles in Britain, guarding the gateway to the Scottish Highlands: Stirling Castle.

Dan explores one of the most ancient castles in Northern Ireland, and a stronghold that holds the key to understanding the tempestuous relationship between Britain and Ireland from the Middle Ages to the 20th century: Carrickfergus Castle.