In the second episode of the forthcoming series, the presenter travels to Fermanagh.
Dan visits the RAF flying boat base on Lough Erne, where he flies in an original Second World War Catalina, an aircraft built for hunting U-boats. He goes to the home of Lord Brookeborough, who tells the story of his grandfather, Northern Ireland's wartime Prime Minister, and how he dealt with the loss of two sons in battle. In Belgium we hear the story of another family who lost a loved one, a Belfast soldier whose body was never recovered, and whose story remained a mystery for nearly 70 years. Dan also meets a group of experts who are trying to bring closure to the families of Second World War soldiers.
In the major new BBC One Northern Ireland series, Dig WW2 With Dan Snow, the series reveals the vital role Northern Ireland played in the Second World War - its strategic location protecting essential supply convoys during the Battle of the Atlantic to the tanks built by Harland & Wolff that would breach enemy lines and the bravery of its soldiers. Dan travels to key sites across Europe where Northern Ireland's influence played a role in the outcome of the war.
Dan Snow said: "As a military historian World War II is a story I thought I knew but now I've come to Northern Ireland where I'm discovering all sorts of incredible stories - secrets, heroism, suffering and valor. This is the untold story of how Northern Ireland played a pivotal role in the war and how its people helped shape the outcome."
Dan visits some of the 350 wartime sites in Northern Ireland - many of which go unnoticed or are buried now - but were central to the defence of the UK and Europe. From the Spitfires and the Flying boats that patrolled the skies, the team dives to the bottom of the Atlantic to reveal the surreal image of Sherman tanks littering the seabed and to the wreck of a U-boat that was one of the most successful in the German fleet.
Series producer John Hayes Fisher added: "What is extraordinary about Second World War history in Northern Ireland is how many sites still remain intact. With just a little digging, these historic places tell the story of the war in ways that history books never can, they bring history to life."
That history puts Northern Ireland at the heart of the Second World War, in one of the most important strategically-based locations the Allied forces would hold. Whether as a launching spot for the Battle of the Atlantic, or a training ground in the days leading up to D-Day, this small part of the United Kingdom had a big part in the war.
"Northern Ireland played a vital role in the Allied victory in the Second World War," added John Hayes-Fisher, "My hope is that this series gives Northern Ireland the recognition and place in history that it deserves."
The series starts on BBC One Northern Ireland on Monday, May 14 at 9.00pm
Dig WW2 With Dan Snow is a 360 Production and Yap Films for BBC Northern Ireland in association with Northern Ireland Screen.