1. Ponte alle Grazie
Here’s how the bridge looks today:
Here’s how it looked around 1875:
It looked like this for a few centuries before it was rebuilt in the late 19th century. Here, for example, is a 17th century engraving of the bridge.
You can read all about this bridge’s fascinating history, begun, as it was, before the Ponte Vecchio! Until the last part of the 19th-century, it looked like this, with the houses on it in which nuns lived.
2. Piazza della Repubblica
Here’s how it looks today:
Here’s how it looked about 125 years ago.
The present appearance of the piazza is the result of the city planning carried out when Florence was the capital of Italy (1865–71), and after, with particularly intense renovation activity in this Piazza between 1885 and 1895. The vintage photo below shows the old houses in the process of demolition, to make way for the showy new Piazza della Repubblica.
A good summary of this very important ground in Florence can be found here: https://en.wikipedia.org/wiki/Piazza_della_Repubblica,_Florence