Royal Observatory Museum of Madrid

The Royal Observatory of Madrid (ROM), located in the Retiro Park, was established in 1790, commissioned by Charles III. Its main building is the work of Juan de Villanueva. The building has an impressive collection of antique instruments used for various astronomical and meteorological activities, such as a meridian circle and an exhibition of precision clocks, and you can admire a replica of William Herschell's enormous telescope, 60 centimetres in diameter and with a focal length of more than 7 metres. In addition, a Foucault pendulum in the central rotunda illustrates the daily rotation of the Earth. The building is crowned by Grubb's large equatorial telescope from 1912. The library, which contains some of the oldest and most extensive documents on astronomy, also deserves special mention.