Students working on the LHC sit outside of Geneva's CERN Physics Laboratory, home of the particle collider.
This photo shows the tunnel of the Large Hadron Collider, where beams of particles pass through the central pipes before colliding with each other.
Detectors like this are placed at the spots where particles collide inside the LHC ring. They include sensitive equipment to detect the presence of exotic particles and their decay products that are created in the collisions.
Physicists watch particle collision data inside the LHC control room.
When particles collide inside the accelerator, they explode into energy that gives rise to new particles. These are often short-lived and decay into other particles. The particle products of collisions are shown as tracks in diagrams like this.
The ATLAS experiment at the Large Hadron Collider is one of the machine's two big all-purpose detectors.
Here, a technician works on the semiconductor tracker barrel of the ATLAS experiment.
Workers move an instrument called a calorimeter inside the ATLAS cavern.
The building that houses the ATLAS experiment and its offices is painted with a mural showing two walls the detector with a collision event superimposed.
A model of the ATLAS detector made out of LEGO blocks by Sascha Mehlhase.
The Compact Muon Solenoid (CMS) experiment is LHC's second major all-purpose detector. Among other projects, it is searching for the elusive theoretical particle called the Higgs boson.
This track is an example of simulated data modelled for the ATLAS detector. The Higgs boson is produced in the collision of two protons at 14 TeV and quickly decays into four muons, a type of heavy electron that is not absorbed by the detector. The tracks of the muons are shown in yellow.
CMS weighs more than 12,000 tons.
Scientists on the accelerator's LHCb (or LHC Beauty) experiment stand in front of their detector, which searches for rare particle decay processes.
A technician works inside the LHC tunnel during the machine's construction.
The ring of the LHC extends 17 miles (27 kilometers) underneath Switzerland and France.
LHC first fired up in 2008, but went offline shortly thereafter when some of its giant magnets failed because of faulty connections.
A fish-eye view of the LHC control room, where physicists watch particle collisions as they take place.
The LHC experiments include thousands of physicists from dozens of countries.
The ALICE experiment at the Large Hadron Collider studies heavy-ion collisions in search of a quark-gluon soup similar to the state of the early universe.
An interior shot of an element of ALICE called the inner tracker.
ALICE's photon spectrometer contains 3,584 lead-tungstate crystals, a material as transparent as ordinary silica glass but with nearly four times the density. When a high-energy particle passes through one of these crystals it will scintillate, allowing the energy of electrons, positrons and photons to be measured through the 17,920 detection channels.
Technicians work on cabling inside the ALICE magnet.