On 27 January 1971, beams collided for the first time in the world’s first hadron collider, the Intersecting Storage Rings (ISR), changing the course of high energy particle physics forever. By 18 May, beams were colliding at the design energy of 26.5 GeV/beam, and by 2 July, the ISR's first results were ready for presentation at the International Conference on Elementary Particles in Amsterdam.

Fifty years later, there have been five hadron colliders in the world, three at CERN and two in the US, each of which has enriched the sum of human knowledge and contributed to innovation in numerous ways.

To celebrate the achievements of the past and look forward to colliders of the future, to the HL-LHC and beyond, CERN is organising a scientific symposium on 14 October 2021. Full details will be communicated at a later date.