When you think about D-Day on this 75th anniversary, there is much that stimulates a kind of awe. Strictly as a military problem the thing was one possible FUBAR (ask a Vet) piled upon another. At the big levels, strategic and operational, it was daunting, to put it mildly.

There was, in the first place, the enemy. In the 20th century, the Germans had built an awesome military reputation. They had fought the whole world, twice, and come very close to victory in 1914 and, again, in 1941.

The only words we can say to veterans are "thank you", Theresa May has told a ceremony to mark the 75th anniversary of the Normandy invasion.

Her words were echoed by French President Emmanuel Macron, who told D-Day veterans gathered in northern France that we owe them "our freedom".

The day of commemorative events began with a lone piper marking the moment the first UK soldiers went ashore.

Donald Trump later told US veterans they were "the pride of the nation".

The US president was at a service at the US war cemetery at Omaha Beach.

Terrible yet inspiring traces of D-Day remain in the Normandy landscape.

On a bluff above the sand and a half-mile from the ocean’s edge at low tide, which was the condition when the first Allied soldiers left their landing craft, a round circle of concrete five feet in diameter provides a collar for a hole in the ground. On the morning of June 6, 1944, the hole was Widerstandsnest (nest of resistance) 62, a German machine-gun emplacement.

A D-Day preview on Memorial Day.