The Palacio de Cristal is a glass and iron pavilion located in Buen Retiro Park in Madrid. The building was designed by Spanish architect Ricardo Velázquez Bosco and constructed in 1887 for the Philippine Exposition, where it originally served as a greenhouse for tropical plants. 

Inspired by the Crystal Palace built in London in 1851, the structure is composed almost entirely of glass supported by an iron framework. The transparent architecture allows natural light to fill the interior space while visually connecting the building with the surrounding park landscape and lake. 

Today the pavilion forms part of the Museo Reina Sofía and is used as a venue for temporary contemporary art exhibitions, making it one of the most recognisable architectural landmarks in Madrid’s Retiro Park.