Pembroke Dock is one of the finest natural harbours in the world and probably Britain's best. Today it is a major oil and natural gas terminal, but when it first started it was designed to supply Britain's navy. That meant it was under threat from Britain's enemies and when the French landed at nearby Fishguard the government got a fright and ordered a major upgrading of the defences.
Among the works undertaken were two gun towers that the locals know as "Martello Towers" after the more famous ones on the south-east coast. They, in turn, were constructed on the pattern of a tower in Corsica that proved surprisingly difficult to take - a mere score of Frenchmen held off British red-coats for hours!
Now managed as a museum trust by local people, the eastern tower is well worth a visit. It is crammed full of fascinating exhibits, some of which feature in this film.