  The Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) experiment is an
array of two 17-meter telescopes located in the Canary Island of La Palma that
observes the very-high energy (VHE) gamma-ray sky in stereoscopic mode since
2009. MAGIC is distinguished by its low-energy threshold of approximately 50
GeV, which grants the system a unique potential in the study of distant
extragalactic sources whose gamma-ray emission is significantly attenuated due
to absorption by the extragalactic background light (EBL). The observation of
non-thermal gamma rays in the GeV-TeV range from extragalactic sources is a
characteristic signature of their relativistic nature and therefore
fundamentally important for our understanding of the physics of these objects.
Since the beginning of its stereo operation, MAGIC has observed a large number
of active galactic nuclei (AGN) of different classes, including several blazars
and distant quasars. In this paper we will review some of the most important
results of these observations.
