During our all too brief visits to Firenze, we spent relatively little time south of the Arno River. However on the day that we went there with the tour group, I recall that our bus was parked over that side. From the timestamp, this would have been taken when we were returning to it.
This shot would have been taken from the Lungarno Serristori. (Lungarno refers to the embankment along the river Arno. Names are then appended to the various sections, such as Lungarno Torrigiani or in this case Lungarno Serristori, with Serristori being the name of a notable Tuscan family.) It's looking across the river toward the Biblioteca Nazionale Centrale di Firenze (the National Central Library of Florence) which was founded in the 18th century and is claimed to be Italy's largest national library. That's the building with the 2 towers in the foreground, which will be found on the Piazza dei Cavalleggeri on the north side. Behind that you can see the belltower of the Santa Croce church.