This impressive art collection was donated to the Catholic Church by the Carrol-Porczyński family and includes works by Rembrandt, Velasquez, Constable, Rubens, Goya, Renoir and many other famous names. Sadly, the paintings are not particularly well labelled or lit, but you'll often have the place all to yourself. Enter from ul Elektoralna.
The museum occupies part of the former Stock Exchange and Bank of Poland building, including the domed rotunda – hung with old master portraits, this room sometimes hosts classical concerts and other events.