AbstractKnowledge of the fundamental constituents of matter has greatly advanced, over the last decades. The Standard Theory of fundamental interactions presents us with a theoretically sound picture, which describes with great accuracy known physical phenomena on most diverse energy and distance scales. These range from 10−16 cm, inside the nucleons, up to large-scale astrophysical bodies, including the early Universe at some nanosecond after the Big-Bang and temperatures of the order of 102 GeV. The picture is not yet completed, however, as we lack the observation of the Higgs boson, predicted in the 100–500 GeV range — a particle associated with the generation of particle masses and with the quantum fluctuations in the primordial Universe. In addition, the Standard Theory is expected to undergo a change of regime in the 103 GeV region, with the appearance of new families of particles, most likely associated with the onset of a new symmetry (supersymmetry). In 1994, the CERN Council approved the construction of the large hadron collider (LHC), a proton–proton collider of a new design to be installed in the existing LEP tunnel, with an energy of 7 TeV per beam and extremely large luminosity, of ∼1034 cm−2 s−1. Construction was started in 1996, with the additional support of the US, Japan, Russia, Canada and other European countries, making the LHC a really global project, the first one in particle physics. After a short review of the physics scenario, I report on the present status of the LHC construction. Special attention is given to technological problems such as the realization of the super-conducting dipoles, following an extensive R&D program with European industries. The construction of the large LHC detectors has required a vast R&D program by a large international community, to overcome the problems posed by the complexity of the collisions and by the large luminosity of the machine.