A celebration was held in Experimental Hall I4 of the Intersecting Storage Rings on 7 November 1969 to mark the 'closing' of the ring tunnel to house the ISR. Work on the site began almost exactly three years earlier, involving the excavation of over a million cubic metres of soil, and in October 1967 construction of the tunnel itself started. The full circumference of almost one kilometre had been completed by December 1969. The main contractor for this construction was the firm Sogene of Italy with the firm Albanese, also of Italy, as subcontractor for the excavation.