For two decades, Festung Guernsey has been restoring the island’s wartime fortifications.
Since 2005, volunteers from Festung Guernsey have been clearing, painting and fixing fortifications that were originally built in Guernsey by the occupying German forces between 1940-45.
Their mission is to ensure that these historical landmarks are maintained for future generations.
Their restoration work at Batterie Mirus was shown to Princess Anne during her Liberation 80 visit in May.
The group has been invited to celebrate their 20th anniversary at Government House.
Festung Guernsey’s Steve Powell says it's an honour.
“For 20 years, we have strived to honour the sacrifices made by those who lived through the occupation and to provide educational opportunities for all who wish to learn about this pivotal period in our history.
"It has been hard work, but the end result is worth it.
"I hope that our work inspires the next generation, and we will continue to see an influx of volunteers who recognise the significance of these fortifications.”
Chairman Paul Bourgaize says he's proud of the projects.
"It can be quite a laborious process.
"Sometimes they are flooded, so we have to pump them out, dry them out and then do concrete repairs, before we have even started putting some paint on the walls.
"Months and months and months of work just to maybe get one room back to how it was.
"Keeping the island's wartime history alive, that is what we focus on."

Guernsey gets behind community café after online appeal
Guernsey Waste warn of the fire hazard of disposable vapes
No rush to ban social media for the under-16s in Guernsey
Guernsey businesses encouraged to use the daily St Malo ferry for European imports
Guernsey's airline to drop its European holiday routes
A total ban on disposable vapes in Guernsey and Jersey is poised to take full effect
Guernsey's Air Display to remain an early evening event
Disgraced Guernsey politician and pastor jailed for 9 years