A solitary poppy in the Boboli Gardens, where I don't think I've spent much time since I was a graduate student, reading Keith Thomas' Religion and the Decline of Magic, day after day, under a tree (I think entrance to the gardens must have been free then - or nearly so - alas, no more);
some more wall art, on the Lung'arno;
a pillar and arch at the entrance to Santa Maria Novella - the chapel in the Green Cloister still has some of my favorite frescoes in the world (admittedly illustrating the dangerous lures of everyday life - dancing, and music-making, and climbing trees to eat forbidden fruit);
a shrine on a street corner;
and the roundabout/carousel on the Piazza della Repubblica.