La Caja Mágica ("The Magic Box'"), also known as the Manzanares Park Tennis Center, is a sports structure located at the Park Manzanares, used for the Madrid Masters tournament in Madrid, Spain. Madrid’s Olympic Tennis Centre. The “Caja Mágica” concept encloses sports and multi-functional buildings but opens up and shapes itself to the various uses projecting a changing and lively silhouette in the cityscape. Its mobile and vibrant skin filters the sunlight, serves as a windbreak and shelters the sports halls in a lightweight shell.