  The observation of cosmic gamma-rays from the ground is based upon the
detection of gamma-ray initiated air showers. At energies between approximately
$10^{11}$ eV and $10^{13}$ eV, the imaging air Cherenkov technique is a
particularly successful approach to observe gamma-ray sources with energy
fluxes as low as $\approx 10^{-13}$ erg\,cm$^{-2}\,$s$^{-1}$. The observations
of gamma-rays in this energy band probe particle acceleration in astrophysical
plasma conditions and are sensitive to high energy phenomena beyond the
standard model of particle physics (e.g., self-annihilating or decaying dark
matter, violation of Lorentz invariance, mixing of photons with light
pseudo-scalars). The current standing of the field and its major instruments
are summarised briefly by presenting selected highlights. A new generation of
ground based gamma-ray instruments is currently under development. The
perspectives and opportunities of these future facilities will be discussed.
