circa 100 BC
OK, the suburbs of Rome Italy are not New York City (yet), but where else can I show off my sewer cover from around 100 BCE? The Romans were famously proud of their hydraulic engineering both aqueducts and the thereby necessary cloaca. And here, unmarked and mostly unnoticed in the meticulously preserved and reconstructed port of Rome, one sewer cover is still doing its original job, preventing grown men and women, not to mention small children and horses, from falling unceremoniously into the sewer.
Why are sewer covers round? And why where they round 2000 years ago?
Drainage, air and a place to clean out those always troubling adipembergers (fatburgs -- according to Google.)
Domus della Fortuna Annonaria near the Viale degli Scavi in the Archeological Park of Ostia Antica, 15 miles south of central Rome.