The mine was named after Lochnagar Street, the British trench from which the gallery was driven. It was one of 19 mines that were placed beneath the German lines on the British section of the Somme front to assist the infantry advance at the start of the battle. The Lochnagar mine was sprung at 7:28 a.m. on 1 July 1916 and left a crater 98 ft (30 m) deep and 330 ft (100 m) wide, which was captured and held by British troops. The attack on either flank was defeated by German small-arms and artillery fire, except on the extreme right flank and just south of La Boisselle, north of the Lochnagar Crater. The crater has been preserved as a memorial and a religious service is held each 1 July. (Wikipedia)
A number of photographs of a crater which was created at the Somme, on the Western Front during World War One.