by Department of Energy, the National Science Foundation, and the Smithsonian Institution. Additional construction funding was provided by Enterprise Ireland (now Science Foundation Ireland) and the Particle Physics and Astronomy Research Council in the United Kingdom. Improvements and upgrades to VERITAS have been made periodically since 2007. Telescope #1 was moved in the summer of 2009 to a new location for better array geometry (and improved gamma-ray sensitivity). Between 2009 and 2011 an upgrade program was carried out that improved the alignment of the VERITAS mirror facets and replaced the level 2 trigger system. Furthermore, in the summer of 2012 all of the camera photomultiplier tubes were upgraded to high-quantum-efficiency tubes, which again increased the sensitivity, especially near the low end of the gamma-ray energy range. Compared to its initial design sensitivity, the actual achieved sensitivity of VERITAS is significantly better with the time required to detect weak gamma-ray sources reduced by more than a factor of two. In June 2017, a celebration was held at the Whipple Observatory to celebrate ten years of VERITAS science. Science VERITAS has a broad science program that combines key aspects of astronomy, exploring the universe in the new waveband of VHE gamma rays, and physics, searching for new particles of phenomena beyond the standard model of particle physics. The basic questions pursued include: understanding cosmic particle acceleration in our Galaxy (with special emphasis on understanding the origin of cosmic rays) and beyond our Galaxy, probing extreme environments near compact objects such as neutron stars and black holes, the nature of dark matter and the intergalactic magnetic field, and whether the speed of light is constant at these extreme gamma-ray energies. The VERITAS observational program includes Galactic sources such as supernova remnants, pulsars, pulsar wind nebulae, binary systems and the enigmatic gamma-ray source at the Galactic Center. Extragalactic sources include active galactic nuclei, starburst galaxies, and gamma-ray bursts. An important component of VERITAS observations is that associated with multi-wavelength and multi-messenger follow up, including fast radio burst (FRB), high energy neutrino, and gravitational wave events. VERITAS has an extensive dark matter program, in which indirect searches are conducted to find VHE gamma rays resulting from the annihilation of dark matter particles. Most of these searches target the Galactic Center and dwarf spheroidal galaxies. Starting in 2017, the VERITAS science program was expanded to include observations in the optical waveband through high-time-resolution measurements of asteroid