Lochnagar Crater:

The largest British mine crater on the Western Front, this was one of several mines exploded under the German front line positions on the Somme on 1st July 1916. A charge of 60,000 lbs (26.8 tons) of Ammonal explosive was blown at 7.28am resulting in a crater 90 feet deep and 300 feet across.

Lochnagar Crater, named after the trench from where the main tunnel was started, is now owned by Englishman Richard Dunning. He saved it from being filled in 1978, and now each year on the 1st July a ceremony is held here to remember men of all sides who fell on the Somme in 1916. 

Units of the 34th Division attacked this area and the nearby village of La Boisselle on 1st July. This formation contained two whole brigades of ‘Pals’ battalions – the Tyneside Irish and the Tyneside Scottish. They suffered many casualties that day – five battalions losing over 500 men each. The 34th Division lost 6,380 officers and men that day. 
I hope that from these photographs you can get a good idea of the sheer size of the crater. I did call for a volunteer to go down to the bottom of the crater to provide some scale - but  surprisingly no-one was willing to! The facts say it is 90 feet deep but standing on the very slippery chalk edging the crater it does look a lot, lot deeper. You certainly wouldn't want to find yourself at the bottom of the crater facing the climb out under fire from the German guns.

An officer of the Royal Flying Corp witnessed the explosion and said that -
“ The whole earth heaved and flared, a tremendous and magnificent column rose up into the sky. There was an ear-splitting roar, drowning all the guns, flinging the machine sideways in the repercussing air. The earth column rose higher and higher to almost 4,000 feet."