The first beam of protons circulated around an ancestor to the Large Hadron Collider at CERN 50 years ago today.
The CERN Electron Storage and Accumulation Ring (known as 'Cesar') was a crucial stepping stone to building particle accelerators and colliders, eventually leading to the LHC and its ground-breaking particle physics.
The machine was first booted up on 18 December 1963, when the first beam circulated around its meagre 24-metre circumference.
As the picture above shows, it was a far cry from the 27-kilometre long LHC, which is the highest-energy collider ever made and generally considered to be one of mankind's greatest engineering achievements.
But it was also a critical development, leading directly to the development of other machines that themselves paved the way for the LHC itself.
Cesar was eventually dismanted in 1968.