Day 1 is really 1/2 day as we arrived mid-afternoon. Ravenna, like Reggio, is a smaller and very charming city. There are certainly tourists, but it isn't the hoards that are in Bologna.
Long ago, Ravenna was the leading city of Western Europe and heir to Rome. As a city built on canals, it was Venice before there was a Venice. And not only did it survive the Dark Ages, it thrived.
Many of the historical points of interest in Ravenna were built 1500 years ago on soft, swampy soil. Subsequently, many of the structures have sunk several meters into the earth. What is most notable of the religious art here is that it was created with mosaic tile, not painted frescos. A good example was our first stop, Mausoleum of Galla Placidia. Built 1400 years ago in honor of Galla Placidias, daughter of Theodosius the Great, it is as remarkable as her life was (too long for here, but well worth Googling her). The structure itself has sunk 2.5 meters into the earth, but luckily the mosaic art has survived! 
