Castles were bastions of power. Yet, what was life like behind their walls? Part 1 of our documentary follows their development from simple wooden fortifications to the most elaborate strongholds and residences. Part 2 examines their military function from the 11th to the 16th century. When the enemy was at their gates, they had to withstand battering rams, catapults and sapping which called for ever new solutions by their defenders until, finally, large-calibre cannons spelt their end.