The Parque del Buen Retiro named by Madrid's king (Park of the Pleasant Retreat) is a large and popular, one and a half square kilometre park in Madrid city centre, not far from the Prado Museum. Once outside the city, Madrid now entirely surrounds the park.

The park was originally the site of a royal palace built in 1632 under the reign King Philip IV. Most of the palace was destroyed during the Napoleonic Wars, leaving a space that was eventually opened to the public in 1868. The few remaining buildings of the palace now house museum collections.

Within the park is the Estanque del Retiro, a large artificial lake. Next to the lake is the Mausoleum of Alfonso XII, featuring a semicircular colonnade and a statue of Alfonso on horseback on a tall pedestal. Around it there are many puppet shows greatly enjoyed by the children there. There are all manner of street performers and fortune tellers. Visitors can also take little boat rides on hired rowing boats or go on a big scheduled one. Many families in Madrid go there on the relaxed summer afternoons.

The park contains the Palacio de Cristal, a glass pavilion inspired by The Crystal Palace in London and designed in 1887 by Ricardo Velázquez Bosco. Velázquez Bosco also designed the park's Palacio de Velázquez. The park also contains 'El Angel Caído', the only statue in the world in honour of Lucifer, the fallen angel, as well as the Forest of the Departed (Bosque de los Ausentes), a memorial monument to commemorate the 191 victims of the 11 March 2004 Madrid attacks.