I came across this today and I never knew about this.
Taken from the May 2022 issue of Physics World.
In 1951, Liverpool, UK, was still marked by bomb damage from the Second World War. Nevertheless, led by Nobel-prizewinning physicist James Chadwick, the city’s university managed to construct a world-leading synchrocyclotron. Built into the Earth underneath the crypt of the city’s partially built cathedral, it was the first of its type that allowed the beam of accelerated particles to be directed at an outside target. By 1968, it was supplanted by machines at CERN in Geneva, and no trace of it remains.