CERN, the European Organization for Nuclear Research, is one of the worlds largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the worlds largest and most complex scientific instruments are used to study the basic constituents of matter the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature. The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions. Founded in 1954, the CERN Laboratory sits astride the FrancoSwiss border near Geneva. It was one of Europes first joint ventures and now has 20 Member States.