Watch Secrets of Great British Castles Season 1 in Australia

Dan heads behind the battlements of Dover Castle, where he descends into an underground lair. There he discovers how a vast network of tunnels have been used as a defense.

Dan looks at the secrets of the Tower of London and those who met their end there. From traitors, to rebels, to royalty, many died at this site.

Dan looks at the walls of Warwick Castle and how they echo with the tales of betrayal, bloodshed and murder. For centuries it was a poisoned chaline to the Earls of Warwick.

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

Situated high on a crag overlooking the river Forth, Stirling Castle guards the gateway to the Scottish Highlands. Location filming, stunning aerial shots, and reconstructions bring to life its turbulent history.

Dan Jones explores the history of Carrickfergus Castle in Co Antrim, one of the most ancient castles in Northern Ireland and a stronghold key to understanding the tempestuous relationship between Britain and Ireland. Dan travels to Rathlin island, where he reveals how hundreds of women and children were massacred in the name of Elizabeth I, and visits the tomb of former governor Arthur Chichester, who began a new colonization strategy using scorched earth tactics and laid waste to much of the land surrounding the town.