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.
There are three courts under the one structure, and a series of retractable roofs. The main stadium has a seating capacity of 12,442. There are two smaller courts in the structure, with Court 1 able to hold 3,500 people, and Court 2 to hold 2,500 people. The seating capacity of Courts 1 and 2 would have been increased if Madrid's bid for the 2016 Summer Olympics had been successful.
In the 2010-11 season, it was the home stadium for the Real Madrid basketball team. It can also be used for concerts and shows. It was the venue for the MTV Europe Music Awards 2010 on 7 November 2010.