You might have an image of Classical Athens as a pristine place, where men in pure white tunics walked serenely between marble buildings.
The Agora was beginning to get marble public buildings at the time of my first book, but Athens was fundamentally mud daub walls with wooden frames and straw or wooden roofs. Many houses were double story - space was short - but three stories was beyond them. To create more space people built their second stories leaning out over the first, just like the famous Shambles in York, England. There were city edicts against building over the street line, which were universally ignored. Walking down a narrow lane in Athens would have been a bit like going down a tunnel. The light would only have appeared in the center of the lane, but you wouldn't walk down the middle because if you did, you were likely as not to get a bucketfull of slops dumped on your head when a slave poured a bucket out a second story window.
The roads were dirt, or more accurately, mud, because the road was the place to toss the household slops and waste. No public garbage collection, of course. Streets sloped inwards to get rainwater and mess away from the walls, same as the mediaeval arrangement. If the street was on a slope then it acted like an open sewer and the muck flowed away. If the street didn't slope, then the muck stayed where it was. A house-proud wife probably had her slaves sweep mess along to outside the neighbors.