This may be a bit off topic as it isn't aviation orientated, however I've been watching the Time Team archaeological series on YouTube and just watched this rather interesting, if a little grim, special episode where they search for the remains of a secret weapon used during the battle of the Somme.

Thanks Harry, I never new about this.
I lost two great uncles that day one serving with the 8th, and the other with the 6th Army.
Regards Alan