A View through Three Arches of the Third Storey of the Colosseum, C.W. Eckersberg
On Google Art Project; downloadable high-resolution file on Wikimedia Commons. The original is in the Statens Museum for Kunst, which has a very large, but over saturated, downloadable file of the image.
While in Rome in the early 19th century, Eckersberg painted this on location, an unusual practice for Danish artists of his time. Though the details are accurate, he combined slightly different views than would actually be seen from this location to make a more pleasing final composition.
