CERN, the European Organization for Nuclear Research, is the worldpsilas largest particle physics centre. It provides state-of-the-art scientific facilities to use in exploring what matter is made of, and what forces hold it together. Observing phenomena at the subatomic level requires extraordinary instruments, particle accelerators and particle detectors. In a particle accelerator, beams of subatomic particles are boosted to nearly the speed of light and then brought into collision with either a stationary target or another beam of accelerated particles coming head-on. Each of these collisions is called an event. Each event is very complex since lots of particles are produced. In order to look for these various particles and decay products, multi-component detectors that study different aspects of an event are built around the collision point. Each component of a modern detector is used for measuring particle energies and momentum, and/or distinguishing different particle types. Most modern particle detectors produce tiny electrical signals that can be treated and recorded as computer data. Detectors in high-energy physics characteristically produce great quantities of data, whose acquisition, reduction and interpretation have made up a significant component of the experimental effort both technically and financially. For the past 60 years, the historic advances in elementary particle physics are linked to the progress in accelerator and detector technologies, as well as in the associated readout electronics technologies. Owing to the continuous evolution in the semiconductor industry, the front-end and readout electronics for High Energy Physics have been evolving to satisfy decade after decade the increasing demands of the experiments. Very deep submicron CMOS FPGAs not only offer speed, density, computational power and flexibility, but also intrinsic radiation tolerance. ASICs and FPGAs are largely used in many different areas in High Energy Physics: controls, monitoring, signal processing, data compression, high-speed data links, online reconstruction and selection of the collision events. This contribution aims at reviewing the important role that FPGAs play in modern High Energy Physics Experiments by presenting some of the most advanced and peculiar applications of FPGAs at CERN.