The National Observatory of Athens (NOA) was established in 1842. Today it is one of the largest research centers in Greece. The activities of NOA are organized in three institutes staffed with high quality scientific, research and technical personnel: the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, the Institute of Environmental Research and Sustainable Development and the Geodynamics Institute. NOA carries out state-of-the-art basic and applied research in collaboration with other world-leading research centers. NOA’s research activities are focused on the terrestrial interior, the Earth’s atmosphere, the near-Earth’s space, the deep space and the astronomical Universe. Basic and applied research is conducted by using observational data from hundreds of ground-based stations and several space probes. The Centre, with its rich scientific outcomes and activities, is linked to entrepreneurship, culture, education and the popularization of science. NOA offers critical social services, such as a daily monitoring of seismicity and issuing earthquake alerts to the Greek State Authorities on a 24/7 basis, weather forecasting, forest fires monitoring, ionospheric activity recording, space weather predictions for the European region, continuation of a 150 years long climatic dataset and operation of one of the largest European telescopes. It also provides the national gate to the European Space Agency.