Carthage Archaeological Park
The vast majority of the ruins at the Carthage Archaeological Park date from Roman-era Carthage rather than the earlier Punic period. The most impressive are the Antonine Baths and Roman Villas. If you have only a few hours, prioritise these two sights and Byrsa Hill, although note that the Carthage Museum atop Byrsa Hill closed in early 2018 for a desperately needed renovation, and no reopening date has been announced. While the park's name is wonderfully evocative, the ruins that comprise it are a disappointment to many visitors. Scattered over a large area, they are scant and poorly presented.
The site lies northeast of the city and is easily reached by the suburban train from Tunis Marine TGM station (0.7DT). You can use the TGM to cover larger distances. Alight at Carthage Hannibal station and take the reasonably steep walk up Rue D'Ampitheatre to the top of Byrsa Hill, the ancient city’s spiritual heart and the location of the Carthage Museum. From the booth here you can purchase your multiple-entry ticket (10DT, camera permit 1DT) to the park. It's valid for one day and allows entry to the widely spread-out group of sights (from the Antonine Baths in the north to the Sanctuary of Tophet in the south it’s a distance of 2km).
From Byrsa Hill make your way back down towards the TGM line, and to the Roman Villas and Antonine Baths. Then head south down busy Rte de la Goulette to visit the Punic Ports and the Sanctuary of Tophet, which is located a short walk from the Carthage Salammbo TGM station.