One of the world's most distinguished small museums, the Frick offers a unique opportunity to view an exceptional trove of Old Masters paintings, furnishings and decorative arts in the luxurious confines of a sumptuous mansion. Pittsburgh steel and railroad tycoon Henry Clay Frick amassed this remarkable trove of artworks over the course of four decades. In 1913 he commissioned Carrère and Hastings to build a 40-room mansion for his holdings (and himself); he took up residence here in 1914 and died five years later. Since the museum's opening in 1919, the building has been expanded twice and the collection has grown by a third. Acoustiguide audio tours (free) are an excellent way to experience the art treasures of this delightful museum.