One of the legacies of the two world wars in Europe is the great volume of weapons, from working tanks and machine guns to artillery and army field bridges, that were left behind. They often ended up in private hands, or, in the case of the military bridges, they are still in use.
One of the strangest of these private collections can be found here on a farm near Pas de Calais in northeastern France, where the white cliffs of Dover can be seen on a clear day.
Clement Davies owns not just an enormous German bunker that housed a naval gun used to shell ships in the English Channel and towns in southern England, but also a massive railway gun and a large arsenal of other weapons.
Davies, whose distant ancestors were from Wales, said the Germans built the bunker on his father's farm after France was defeated in 1940. When the bunker and several others in the area were overrun by Canadian troops in September 1944, it became family property again and it has since been turned into a business, drawing about 35,000 tourists a year.
The Germans destroyed four farms in the area to establish a series of batteries, he said.
The original naval gun was seized after the war by the French army, which then "loaned" his father a German K-5, 280-millimetre railway gun, but Davies eventually acquired ownership of it after the French government lost interest in the K-5. (It's a long story).
Some 15,000 bunkers, 20,000 machine-gun nests, 5,000 coastal batteries and thousands of minefields and other obstacles were built along the coast from the French-Spanish border all the way to Norway. They were part of Hitler's "Atlantic Wall" and were intended to defeat or at least stall a seaborne invasion until the German army could respond in force.
Much of it is still in place, although several coastal batteries were destroyed to make way for the underground tunnel that connects England and France.
Bunkers were built in all shapes and sizes; some up close to the sea, while others were situated far back, firing blind with directions provided by forward observation posts.
Several famous battles were fought to disable the bunkers on D-Day, including daring assaults by paratroopers and commandos.
Along the Normandy coast, the Germans built some steel and concrete bunkers to look like houses, many of which have since been converted to real houses.
In the port of Ouistreham, the eastern flank of the landing zone, a six-storey German command bunker, privately owned by collector Fabrice Corbin, fits effortlessly into a residential neighbourhood.
In the courtyard of Le Grand Bunker, the landing craft used by Tom Hanks in the movie Saving Private Ryan, and which was used on D-Day, is on display along with an assortment of heavy weapons and tanks, which almost every town seems to own.
A powerful range finder on the top floor offers a detailed 360-degree view of the countryside and was used to direct fire from gun positions in the rear. It was overlooked by Allied planners on D-Day and went undetected for three days when British army engineers were ordered to inspect the site. Following a short battle, the 50 German soldiers inside surrendered.
Corbin was accused of being a grave robber when he recovered a spitfire from the estuary at Ouistreham that still held the body of its Australian pilot. He turned over the body, but put the spitfire in the courtyard of his home. Eventually, he relinquished it (reluctantly) to the Australians.
Liberty Park in Overloon, Netherlands, contains the largest collection of vintage military vehicles in Europe -- nearly 300 -- and many of them are in working condition, including tanks and a range of other vehicles. They were originally part of a private collection, which was donated to the museum.
The Allies left behind thousands of vehicles and other equipment; some of it was given to the new armies formed in Holland, France and Belgium after the war, while much of the damaged war material was simply abandoned or sold to farmers and construction companies that needed heavy equipment.
The most sinister of all the German bunker projects, however, is La Coupole, or The Dome, also located near Calais. The huge network of underground galleries was to be used to assemble and launch V-2 rockets in rapid succession against Britain, but it was abandoned in 1944 just weeks before it was due to be completed.
It was neglected for 50 years and became a playground for local children before it was reopened and turned into a museum, attracting 120,000 visitors a year, more than double the number that visit the Juno Beach museum.
A tour guide noted the U.S. space program was a direct beneficiary of Nazi slave labour that helped German scientist Werner von Braun develop the Nazi rocket program.
Today, the museum tells the story of the space race as much as the horrors that it represents. Thousands of slave labourers died building it, making it a death bunker like no other.