Rem Koolhaas, a Dutch architect, created the Casa da Msica, a concert hall in Porto, Portugal, to house the institution of the same name and its three orchestras, the Orquestra Nacional do Porto, Orquestra Barroca, and Remix Ensemble. Its development, which began in 1999 and was completed in early 2005, six years ahead of schedule, was a component of the Porto 2001-European Capital of Culture initiative. It was soon recognised as the city's symbol.

The Rotunda da Boavista, the city's primary traffic circle, is located right next to the Casa da Msica. The area where the structure now stands was once used as a storage facility for trams that were no longer in use. Building it cost 100 million euros. The construction of its peculiar shape presented significant engineering hurdles during the constructing process. The building was built by Ove Arup, a London-based company, and Afassociados, a Porto-based company.

The building's design has received a lot of praise all across the world. It was dubbed "the most attractive project ever erected by the architect Rem Koolhaas" by Pepe Ouroussoff of the New York Times, who also described it as "a structure whose intellectual zeal matched its physical beauty." Additionally, he contrasted it with the "exuberant design" of the Guggenheim Museum by Frank Gehry in Bilbao, Spain. Compared to the Walt Disney Music Hall in Los Angeles and the Philharmonic theatre in Paris, it is one of the most significant concert halls created in the last 100 years, according to the author.

Although Cl and Lou Reed performed at the inauguration event on April 14, 2005, Portuguese President Jorge Sampaio officially opened the building the next day, on April 15. There were numerous significant politicians and members of the local community in attendance, including the prime minister.

Although there are two main auditoriums at the Casa da Msica, numerous smaller spaces can be easily transformed for events like concerts (workshops, educational activities, etc). The larger auditorium can accommodate up to 1,238 people at a time, but this number may change depending on the event.

The smaller auditorium is quite adaptable and has no set seating arrangement. The auditorium can typically accommodate 300 people sat and 650 standing, though this can vary greatly depending on the size and placement of the stage, the seating configuration, the presence and size of sound and recording equipment, etc.

Though it is still under construction, the restaurant at the top of the structure can accommodate more than 250 diners.