The Lochnagar Crater was created by a large mine placed beneath the German front lines on the first day of the Battle of the Somme, it was one of 19 mines that were placed beneath the German lines from the British section of the Somme front, to assist the infantry advance at the start of the battle.
The British named the mine after ‘Lochnagar Street’, a British trench where the Tunnelling Companies of the Royal Engineers dug a shaft down about 90 feet deep into the chalk; then excavated some 300 yards towards the German lines to place 60,000 lbs (27 tons) of ammonal explosive in two large adjacent underground chambers 60 feet apart. Its aim was to destroy a formidable strongpoint called ‘Schwaben Höhe’ (Swabian Heights) in the German front line, south of the village of La Boisselle in the Somme département.