SCIENCE & FRONTIER RESEARCH · SWITZERLAND
CERN
The laboratory where particles collide — and where the web was born
Original schematic illustration · created for the Atlas — stylised technical drawing, not a photograph.
01 In brief
CERN, the European Organization for Nuclear Research, sits on the Franco-Swiss border just outside Geneva. Founded in 1954 as one of Europe's first joint scientific ventures after the Second World War, it is today an intergovernmental laboratory with 25 member states, dedicated to fundamental physics: asking what matter is, where it comes from, and how the fundamental forces of nature fit together.
The laboratory's best-known instrument is the Large Hadron Collider (LHC), a 27-kilometre ring of superconducting magnets buried about 100 metres underground, in which counter-rotating beams of protons are accelerated to nearly the speed of light and smashed into one another at four giant detectors: ATLAS, CMS, ALICE and LHCb. In June 2026 the LHC completed its third data-taking run and entered Long Shutdown 3, a multi-year upgrade pause that will prepare the machine for even higher energies.
02 Why it's interesting
- 01 It recreates, for a fraction of a second, the conditions that existed moments after the Big Bang — allowing researchers to study matter in states that no other laboratory on Earth can produce.
- 02 The engineering is superhuman in scale: thousands of superconducting magnets steer beams around a 27-kilometre ring, cooled close to absolute zero, synchronized to nanosecond precision.
- 03 It is the birthplace of the World Wide Web, invented at CERN in 1989 by Tim Berners-Lee as a way for physicists to share information — and released to the world as an open, royalty-free standard.
- 04 It is science without borders: researchers from institutes in well over a hundred countries work side by side, and the results are published openly for anyone to use.
03 How it works
CERN's method is to accelerate particles to enormous energies and then crash them together, converting that energy into new particles as described by Einstein's E=mc².
Beams of protons (or heavy ions) are fed through a chain of ever-faster accelerators before being injected into the LHC's two beam pipes. There, radio-frequency cavities add energy on each lap while some 1,200 superconducting dipole magnets bend the beams around the ring — the magnets must be chilled to roughly 1.9 kelvin, colder than outer space, for their coils to superconduct.
Where the beams cross, collisions occur up to a billion times per second. Surrounding each collision point stands a detector the size of a building — layers of trackers, calorimeters and muon chambers that reconstruct the spray of particles from each collision, like a high-speed camera photographing an explosion in three dimensions.
The sheer volume of data is a physics problem in itself: experiments filter the collision stream in real time and distribute the surviving events to a worldwide computing grid, where thousands of scientists analyze them in the search for rare signals — the way the Higgs boson was found in 2012.
| LHC circumference | 27 km (26,659 m) |
|---|---|
| Collision energy (Run 3, 2022–2026) | 13.6 TeV |
| Tunnel depth | ~100 m underground |
| Main experiments | ATLAS · CMS · ALICE · LHCb |
| Status (from June 2026) | Long Shutdown 3 upgrades |
| Founded | 1954 · 25 member states |
Figures per CERN's published LHC and institutional information; Run 3 concluded 29 June 2026.
04 The organisation behind it
CERN is an intergovernmental organization funded by contributions from its member states and run for the benefit of science rather than profit. A permanent staff operates the accelerators and laboratories, while the experiments themselves are built and run by international collaborations — each detector is a partnership of hundreds of universities and national institutes. Any member-state scientist can propose research, and access to the facilities is decided on scientific merit.
05 In the real world
The tools of particle physics have a long history of spilling into everyday life. Detector technology developed for physics experiments underpins modern medical imaging, and particle beams are used directly in cancer therapy. The World Wide Web — invented here for information sharing — is CERN's most famous gift to society, alongside the distributed computing techniques now used across data-intensive science.
CERN also trains generations of engineers and physicists who carry its precision culture into industry, from medical devices to aerospace.
06 Can you visit?
Yes — CERN welcomes the public at its visitor centre near Meyrin and offers guided tours of the site, though underground visits to the accelerators are limited and depend on the technical schedule. During Long Shutdown 3, access patterns may differ from normal operations.
Check the official visits pages for current availability and booking; the Geneva-area site is easily reached by public transport from the city centre.