You don’t walk, you doolesha
Doolesha is an ancient Tunisian dialect phrase that basically translates to "leisurely strolling," and it's the only way to explore the old medina (city). Long before there was UNESCO, or any vehicle broader than a horse's flank, the Arabs came and erected the UNESCO World Heritage-listed medina of Carthage. The ancient city was built around the Zaytouna Mosque (accessible to tourists; ladies should cover their hair and everyone should cover their limbs), which may be used as a compass, but you will get lost at some point.
The hoots, whistles, kisses, and 'compliments' prevalent in so many places throughout the world will be the soundtrack to your walks, especially in the souk and downtown. Dark shades and headphones can assist to filter out the light and drown out the sounds.
A day excursion to Dougga is certainly worth the effort if you're willing to drive farther away. It's difficult to believe that such a well-preserved Roman city, approximately two hours from Tunis, is devoid of tourists. You'll feel transported back in time as you wander alone through the old alleys and temples, as if you've been transported back to when Romans trod the same paths.