Seaport with the Embarkation of the Queen of Sheba (1648), Claude
These paintings above and below are two of three directly compared, hung together in one half of Room 2. Just by looking at and comparing these two the title of the exhibition becomes clear. The (similiar) use of light and composition still has quite an impact on the viewer.
Dido building Carthage, or The Rise of the Carthaginian Empire (1815), JMW Turner
Sun rising through vapour: Fishermen cleaning and selling fish (before 1807), JMW Turner
These two Turner's above and below were not directly compared by the gallery, but I like the contrast between them. Although they both share the seascape subject matter and use light to great effect, they are opposite in other ways: warm/cool, day/night, sunlight/moonlight, sharp/soft, etc.
Keelman Heaving in Coals by Night (1835), JMW Turner