The European CTA project (Cherenkov Telescope Array) consists of about 100 telescopes of varying diameters: the largest ones will have a diameter of 23 m. They will be installed in the Canary Islands and in Chile. They are destined for the detection of the gamma radiation that comes from different sources in the Universe, such as stars from the Milky Way and distant galaxies. When very energetic photons enter our atmosphere, radiation is produced by a mechanism discovered by the Soviet physicist Pavel Cherenkov. By observing this light simultaneously with several telescopes, one can find from where these photons come and what their energy is, furnishing vital information on the nature and mechanism of their sources.