Two conjoined churches and a narrow house make up this unique complex, which is part of Porto's history. Τhe two churches, Igreja do Carmo and Igreja dos Carmelitas, are separated by the "Casa Escondida" (Hidden House). Tiny though it may be, this house is historically significant. A popular story claims that the house was built to prevent the monks of Igreja do Carmo from contacting the nuns of Igreja dos Carmelitas. Another explanation is that the Vatican did not allow two churches to be built side by side. Most likely, however, the three-story house, which was inhabited until the 1980s, was built for purely aesthetic reasons. The Casa Escondida served as a chaplain residence and housed the artists who worked on the decoration of the churches, as well as the doctors who worked at the order's hospital. This unusual construction is significant because secret meetings took place there during important times in Porto's history.