They were shown around by staff and volunteers from VisitGuernsey, Festung Guernsey, the Guernsey Armouries and the Guernsey Military History Company, with access allowed to a number of World War II era defences, including those that are open to the public and some which are privately owned.
The MP4 and MP3 Observation Towers at Pleinmont, the Germany Military Underground Hospital in St Andrews, and the German Naval HQ in St Peter Port, and the Batterie Scharnhorst, Batterie Mirus and Batterie Dolmen are among those filmed.
Pictured: The production crew during their visit to Guernsey.
The documentary, which airs at 20:00 tonight on Yesterday (UKTV), explores various locations occupied by the Nazi forces, with the fortifications giving up some of ‘Hitler’s tactics and targets’.
The series has already been aired in Poland, the United States (screened under the title Secret Nazi Ruins) and the Benelux region, while it will be screened in Canada next year.
Pictured above and top: Images from the VisitGuernsey website. More details HERE.