The Giant Magellan Telescope project is an international collaboration to design, build and operate a 25m telescope for research in astrophysics and cosmology. The GMT primary mirror is comprised of seven 8.4m diameter segments, providing both a collecting area and diffraction-limited image concentration that are an order of magnitude better than those offered by current facilities. The telescope will be located at Las Campanas Observatory in Chile. With its large collecting area and state of the art adaptive optics system the GMT will have a uniquely powerful combination of sensitivity and angular resolution. I will describe how the GMT can advance our understanding of a broad range of astronomy and astrophysics. Key areas of the GMT science program range from studies of planets in orbit around nearby stars to the observations of galaxy formation in the first few hundred million years after the big bang. State of the art instruments will allow us to measure the masses of black holes at the centers of galaxies over a broad range of redshifts and to probe the evolution of galaxy structures – spiral disks, bars, bulges – as the Hubble sequence came into being. The greatest excitement for any new facility of this scale, however, is the potential for new and unexpected discoveries and I will discuss how GMT will open new discovery space.