There are many interesting and world renowned museums in Lisbon, your only problem will be fitting them all into your stay. Surely the most prestigious is the Museu Nacional de Arte Antiga (National Museum of Ancient Art), but coming not far behind is Museu Calouste Gulbenkian (Calouste Gulbenkian Museum) and the Museu do Azulejo (Museum of Portuguese-style Tile Mosaics). For something more contemporary then the Berardo Collection Museum has a good collection of modern art. If you are a fan of coaches then the Museu Nacional dos Coches has the largest collection of them in the world.