This set of negatives was found in the catacombs and shows works associated with the construction of the Nimrod Experimental Hall and digging the pit that became the accelerator ring in 1957.
The negatives were each tucked into envelopes marked UNCLASSIFIED; they are all degrading so smell strongly of vinegar. The quality leaves much to be desired but I was improvising a dark room and making extensive use of PhotoShop which is why the skies appear overly thunderous.
There is also a photograph commemorating the excavations dated 28th November 1957:
