Aryabhatta Research Institute of observational sciencES (ARIES) was founded on 22 March, 2004 when a 50-year-old State Observatory (well known as Uttar Pradesh State Observatory (UPSO) till the creation of Uttarakhand State on 9 November, 2000) was converted into an autonomous research institution under the Department of Science and Technology (DST), Government of India. Since its inception in 2004 from UPSO to the present state, ARIES is devoted to research and development (R&D) in Astronomy & Astrophysics and Atmospheric Sciences. World-class national observing facilities like the 3.6 m (Asia’s largest) Devasthal Optical Telescope (DOT) and Stratosphere-Troposphere (ST) Radar have been established at the institute after decade-long efforts. For solar observations, ARIES has a dedicated 15 cm optical telescope, while for stellar observations in the optical and Near-infrared (NIR) band, ARIES operates four telescopes - 1.04m Sampurnanand telescope (ST), 1.30m Devasthal Fast Optical Telescope (DFOT), 3.6m DOT and the recently commissioned 4.0m International Liquid Mirror Telescope (ILMT). ARIES has also expanded its horizon to theoretical and numerical studies in Relativistic Astrophysics to strengthen its scientific contribution.