By Steven McKenzie
Highlands and Islands reporter, BBC Scotland news website
A picture from the RCAHMS archives of construction of a gun emplacement in 1913
Faces caked with dust, a group of construction workers pause from their work building military defences for a rare photograph.
The look-out posts and gun batteries in Cromarty in the Highlands are among the finest surviving examples in Scotland.
The military gun emplacements were built along the coast to protect and defend a naval anchorage in the firth.
Allan Kilpatrick, of the Royal Commission on Ancient and Historical Monuments of Scotland, said they should be considered as archaeology.
He said: "Very few of the people who served in them are still alive."
The buildings - most are empty shells with rusting metal doors, while others are overgrown with weeds - were in use during World War I.
They were used again, and also added to, in World War II when they played a role in preparing for the D-Day landings on the beaches of Normandy.
The photograph above dates from August 1913.
Mr Kilpatrick, who used to play in some of the Cromarty defences as a boy, said the commission was actively recording where the sites were around Scotland.
He said: "The defences in Cromarty are among the best on mainland Scotland.
"Most have not been touched by vandalism and some remain in such a good condition that you can still see the camouflage paint."
Mr Kilpatrick added: "But these buildings were not built to survive for hundreds of years and there is nothing being done in terms of preservation.
"They should be considered as archaeology and I've been banging away on this issue locally whenever I'm up north taking people around the remains for Highland Archaeology Festival."
Details and images of the defences at Cromarty are held by the commission and the Historic Environment Record, which this year was made available online.
While the guns were never fired in anger, Mr Kilpatrick believes they may have played a part during exercises on both sides of the Moray Firth to prepare Allied troops for the D-Day Landings of 1944.
Coastal defences were built on North and South Sutor in Cromarty.
The battery at South Sutor is "probably the most complete" surviving coast battery in Scotland, according the Historic Environment Record.
The guns were operated by the Royal Navy.
Inver, near Tain, on the Ross-shire side along with small communities on the Nairn-shire coast were cleared of residents so training could be done in secret.
Bill Bartlam, who co-authored the book World War II in Moray with Ian Keiller, was an adjutant in a tank regiment that took part in the rehearsals.
He said: "The topography of Burghead Bay was found to be very similar to that of the beaches selected for the landings.
"The exercises for D-Day invasion had to be carried out in secret so the landward side of the bay was evacuated of all the people and animals down as far as the community of Dyke.
"Those who were moved out were accommodated elsewhere for several months."
Simulations involved landing tanks on the shore and towards the end of the period of training, live firing.
Mr Bartlam said: "The most spectacular of the live firing were rocket propelled weapons which were fired off ships with a whoosh and went screaming up into the sky before landing on the shore."
Tank troops were billeted at Fort George - an 18th Century fortification at Ardersier near Inverness built in the aftermath of the 1746 Battle of Culloden.
Mr Bartlam said: "The tanks would run on the roads from Burghead to Fort George. There wasn't a fence post left unscathed, but after the exercises every one was reinstated."
The army veteran often travelled between a headquarters set up in Aberlour House and Fort George.
One night, he returned to Ardersier to a situation almost on a par with a Ministry of Defence laptop being left on a train today.
Mr Bartlam said: "Maps of the actual beaches to be landed on in France were secret, but a CO had pinned up his in full view in his squadron office.
"I didn't know what I should do. Should I make a fuss, or hope it would be missed among the other maps on the wall. Fortunately, he recognised his mistake and took it down."
Covert operations in preparation for D-Day included the taking of soil samples from beaches along the coasts of Holland and France.
Margaret McColville's husband, Donald, was a major in the Royal Engineers and with other sappers was tasked with retrieving samples for analysis to determine whether the ground could take the weight of heavy armoured vehicles.
She said: "They were blacked up and went out in small boats to the beaches to take the samples."
Mr Bartlam, who was aware of these dangerous missions, said: "Those who went and stood on those beaches before the landings were very brave."