Gamma-Ray Bursts (GRBs) are the most luminous objects in the Universe.
Their origins are considered to be a collapsing death of a massive
star, or a neutron star merging with another neutron star or with a
blackhole. However, the physical processes happening in the objects
are not yet revealed well. A long-awaited detection by Cherenkov
telescopes will be a key ingredient to elucidate the GRB emission
mechanism. In this seminar, observations of GRBs with MAGIC telescopes
are reviewed, and the expected physics cases with Large Size
Telescopes of Cherenkov Telescope Array project are introduced.