A couple more interesting pictures appeared on Twitter tonight.
The first of these was posted by Ste Trombetti, and shows the Arch of Titus in 1848 (!). The photo is in the Getty archive, and was taken by Count Jean-François-Charles-André Flachéron (French, 1813-1883). Through the arch, the Meta Sudans is visible, in its truncated 19th century state.
Here it is:
The next item is a photograph which was found by searching on “Collina della Velia”, i.e. the little Velian hill. This hill was completely levelled by Mussolini, in building the Via del Foro Imperiali. This old photograph shows the black base of the Colossus of Nero, which existed until Mussolini removed it. The black item below the Colosseum is the base.
I found it on Flickr here. Here it is:
Finally let’s include an aerial view of the whole region, from a 2009 exhibition here. Click on it to get a very large photo!
The base of the Colossus is in the shade of the Colosseum, but I think the rectangle can be made out if you zoom:
There seem to be very few photographs of this obscure item.