Tower of Hercules in Spain was still in use, and even given a bit of a facelift in the late 1700s [an additional story was added to handle modern equipment] and it is actually still fundctioning as a light house. Not sure if I can find my pictures of it, I think they were in my moms house when it burned with most of my stuff from teh 70s.
The roman build Baths in Bath are still there, and were in use up until this century, and in Nimes, le Maison Carree has been in constant use since its construction - was converted into a christian church back in the day. Amphitheaters are still dotted around france spain and northern africa.
On Sicily and Sardinia, there are stacked stone structures still in use as grainaries and shepherds huts.
And surely there were ancient crazy cat ladies who wouldnt mind the smell … =)