The “Meta Sudans” was a fountain that stood next to the Colosseum. The remains of the core were demolished by Mussolini in the 1930s, so there are quite a few photographs around. Every so often I come across another.
Here’s one that I found on Twitter, published on 11 Jan 2018. It is unusual, because it shows the monument from an unusual angle, from the Palatine hill. Nice to have it!