This is a History Extra production.

If you ask most people what comes to mind when they think of D-Day,

they might offer up a description of a beach covered in bodies and trap-room,

with surviving troops valiantly making their way onto the shore. Or perhaps they might envisage a paratrooper

jumping out of a sky train, hurtling down towards the earth in a hail of bullets.

But they might be less sure about what happened to these men after they made it behind enemy lines.

What else did the 6th of June 1944 have in store as the Allies pushed deeper

into the Normandy countryside? In the third and final episode of D-Day, Land, Air and Sea,

I'll be speaking to the author and historian Giles Milton about the ground campaign on D-Day,

and how Allied troops fended off the first major German counter-attacks.

But first, I asked Giles to take the story back a little bit further

and briefly summarise how the planning for D-Day began.

Yeah, I mean, D-Day had been in the planning for years, in fact.

I mean, serious planning dated right back to 1942.

And of course, Stalin, whose Red Army was suffering enormous losses on the Eastern Front,

he was pressing for the Western Allies, the Americans and the Brits and the Canadians,

to launch this invasion to liberate France and open up a second front.

But the Allies didn't feel they were in a

position to be able to do this for several years. And in fact, it wasn't until December of 1943,

at Stalin's insistence that General Eisenhower was named as the Supreme Commander. And from that

point on, in fact, throughout 1943 and early months of

1944, thousands of American troops begin pouring into the UK and begin training for this mass

...