  Very High Energy (VHE) gamma rays constitute one of the main pillars of high
energy astrophysics. Gamma rays are produced under extreme relativistic
conditions in the Universe. VHE gamma$ rays can be detected indirectly on the
ground. Detection of these energetic photons poses several technological
challenges. Firstly, even though gamma rays are highly penetrative, the Earth's
atmosphere is opaque to them. Secondly, these gamma rays are to be detected
against the overwhelming background of cosmic rays. When a VHE gamma ray
arrives at the top of the atmosphere it produces charged secondaries. These
charged particles produce Cherenkov flashes in the optical band. Even though
the first attempts to detect these Cherenkov flashes were made almost 70 years
ago, it took several decades of relentless efforts to streamline the technique.
Ground-based VHE gamma-ray astronomy has now established itself as one of the
crucial branches of conventional high energy astronomy to study the
relativistic Universe. In this article we look back and present a historical
perspective followed by a discussion on the current status and finally what
lies ahead.
