So, there were so many that were amazing, I'm only embedding a few pictures, but they all link to the albums they're in.
I love this sea Monster so much.
Santa Cecelia's Church had stunning mosaics, alas, the best ones were behind a locked door, so pictures aren't particularly artful:
Santa Maria Majore, also Amazing.
And finally, the Museum of the city of Rome:
Again, I'm focusing on material-related stuff here... non-mosaic/glass is at
my flicker account.