麻豆社

An area of the Elveden Estate became known as the "most secret place on earth" in 1916, after it was used for top-secret tank training.

Around a million sandbags were used to recreate the Somme, complete with trenches.

Tank crews used the area to practice machine gun fire.

Today all that remains is a wall riddled with bullet holes.

The 100th anniversary of the first use of a tank in battle - on 15 September 1916 at The Somme - is being commemorated.