Trenches where metal detectors still find unexploded ordnance and remains; creating a dangerous archaeological site actively changing soil chemistry.
Rupert Gietl (Arc-Team), CC BY 4.0, via Wikimedia Commons
The century-long cleanup
The Battle of the Somme, which raged from July to November 1916, was one of the deadliest in human history, resulting in over one million casualties. The battlefield is a unique and dangerous archaeological site. The sheer volume of munitions used was immense; the British fired over 1.5 million shells in the preliminary bombardment alone. An estimated one in four of all shells fired on the Western Front failed to detonate. This has resulted in a deadly, century-long "iron harvest" (moisson de fer).
Each year, farmers in the Somme region plow up tons of unexploded ordnance. Shells, grenades, and bullets are regularly brought to the surface. The French state's bomb disposal units, or démineurs, are permanently stationed in the region to handle this lethal harvest. These teams recover approximately 900 tons of unexploded munitions annually across France. The process is slow and perilous, turning agricultural fields into active hazardous material sites. Archaeologists working here do not use shovels casually; they use metal detectors and ground-penetrating radar, followed by cautious, forensic excavation. Modern technologies like LiDAR are also used to map the faint outlines of trenches and shell craters no longer visible on the ground.
A battlefield's chemical legacy
The archaeology of the Somme includes physical artifacts and, the soil itself. The millions of rusting shells and bullets have been altering the region's soil chemistry for over a century. As shell casings corrode, they leach heavy metals into the surrounding earth. Studies of former battlefields show significant enrichment of lead (Pb) and copper (Cu) in the soil. Lead comes from the millions of shrapnel balls and bullets, while copper and zinc are components of shell casings and fuses.
This contamination has lasting effects. Lead concentrations can be four times higher than regional baseline values. These toxic elements can inhibit plant growth and present long-term environmental risks. The battle also physically altered the landscape through a process called "bombturbation." Massive shell craters, some tens of meters wide, inverted soil layers, bringing the deep chalk substrate to the surface and mixing it with topsoil. This process, combined with the chemical residue and the decomposition of organic material, including human remains, has created a completely new soil profile in many parts of the former front line. This makes the Somme an open-air laboratory for studying the long-term environmental consequences of industrial warfare.
💡Fun Facts
The Thiepval Memorial to the Missing of the Somme lists the names of over 72,000 British and Commonwealth soldiers who died in the Somme sector with no known grave.
The British Army issued its soldiers with a single identity tag made of compressed cardboard fiber, which quickly decomposed in the wet conditions, complicating the identification of remains.
During excavations, archaeologists often find multiple layers of duckboards at the bottom of trenches, showing how they were rebuilt and raised as the trenches flooded with mud and water.
Some of the most poignant archaeological finds are personal items like razors and tins of food, as well as trench art, objects carved by soldiers from shell casings and other battlefield debris.
The Historial, Museum of the Great War in Péronne is open daily. April-September: 9:30 AM - 6:00 PM. October-March: 9:30 AM - 5:00 PM (closed Wednesdays).
Admission
Varies; check the official website for current ticket prices.
Accessibility
The Historial museum is accessible and has the "Tourism & Handicap" label. The surrounding battlefields are open countryside with uneven terrain, often on private farmland, requiring caution.
