A friend and I went on a tour with Murielle and Frederic Castier through battlefields, monuments and cemeteries of the Somme recently, and it was a phenominal experience. They are both incredibly knowledgeable and clearly have a very strong passion for the history of the area. They help a person experience the sites and the history of it in such a way that it really helps in trying to understand the tragedy and scale of it all, if such a thing is even possible.  We had a few tours in the region by various guides, and while the were all largely positive experiences, Murielle and Frederic stood out as exceptional. 

For future tours in this area, I will always try to book them if possible.