Whew! That was labour intensive. That's the Colosseum at the top of the hill - those Romans knew how to sort out the drainage and keep the grass (or whatever) in the Arena dry. They weren't bad at columns, arches, statues and thingies... and they sorted those barbarians out.
I've now found my copy of The Life of Brian and Reg confirmed that the Romans sorted the following: the aqueducts, sanitation, the roads, irrigation, Medicine, Education, Health, wine, Public baths, made the streets safe to walk, kept order, the freshwater system and peace. Since our visit I would like to add that the Romans also gave us the Pantheon.