A short introduction to gamma-ray astronomy, a new field in astronomy and astroparticle physics, will be given. The currently running ground-based Imaging Atmospheric Cherenkov Telescopes of the H.E.S.S., MAGIC and VERITAS experiments are introduced. CTA, the Cherenkov Telescope Array, is an international project for the next generation of observatories in this field, extending the accessible energy range from 20 GeV to 300 TeV. The status of the project and its technical challenges are described. The sensitivity in the core energy range will be dominated by up to 40 Medium Size Telescopes. These Cherenkov telescopes with a reflector with a diameter of 12 m, are currently in the prototype phase. A full-size mechanical prototype has been constructed in Berlin. Different prototype mirrors have been developed, tested and are mounted on the prototype. Two camera prototypes were built and tested. A report concentrating on aspects of the design, commissioning and performance will be given.