The four LHC experiments (ALICE, ATLAS, CMS e LHCb) will produce about 15 Petabytes of data during each of the foreseen ten years of operation - this is equivalent to 100 000 DVDs per year. This huge amount of data must be stored and made available to researchers all over the world. Such an immense task cannot be completed using traditional network and computing resources, no matter how powerful.A new method for handling data is essential: the Grid, a novel global computing infrastructure. As the Web was invented at CERN a quarter of a century ago to satisfy the needs of scientific collaboration at that time, the Grid is the answer to fulfil the demands of data analysis in today's particle physics community.