Gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. The Cherenkov Telescope Array (CTA) is an international initiative to build the next-generation ground-based gamma-ray observatory which will have a factor of 5-10 improvement in sensitivity in the 100 GeV - 10 TeV range and an extension to energies well below 100 GeV and above 100 TeV. CTA is planned to consist of two arrays (one in the North and another in the South Hemisphere) and will provide the deepest insight ever reached into the non-thermal high-energy Universe and its particle accelerators.