He's using what must be the core downtown area of Florence, Italy. Matching the picture in the post - on google maps, what is bounded by SS67 road on the north side of the Arno river: counterclockwise to Piazza della Liberta and back to the river; and on the south side the road down to Porta Romana and back to the river.

That section eyeballs to be around roughly ~1.5 mi across. Larger than 2000 ft but a lot less than 5.5 mi.