The incredible Roma Ieri Oggi website continues to post old photographs on the web. This one here is a view of the piazza of the Colosseum, but looking up the Sacred Way to the Arch of Titus. It’s high quality, and can be zoomed in to an amazing extent.
I’ve snipped the portion showing the Meta Sudans, the now-demolished ancient fountain that once stood next to the Colosseum. Only the core of the lower half remained by 1865, when Altobelli and Molins made this image.