Age and beauty go hand in hand on the TGM – the Tunis/ Goulette/Marsa light railway – from which 3,000 years of history can be viewed in just 30 minutes.

The track – among the oldest in North Africa – was laid by a British industrialist in the 19th century. It starts near one of the Arab world’s best-preserved medinas, moves on to one of the Mediterranean’s most beautiful villages and ends at a palm-lined curve of sandy beach – passing, en route, architecture that reaches back through the 16th century, and Charles V, to the 7th-century Arab conquest and the ancient days of Roman legions and Hannibal’s Carthage. Do you know any better way to spend half an hour?

The start: the city of Tunis used to be contained within the medina walls, but then the 19th-century colonial French built a new town around the old and the sprawl began. Make your way along the main boulevard of the French town, Avenue Habib Bourguiba: it ends at Tunis Marine station, where the little trains of the TGM start their journey towards the elegant stations of the suburbs.

Stop one: there are two reasons to get out at Goulette Vieille, just across the lagoon from the city and at the beginning of the coastal strip. The first is to see the monumental fort: built in the 16th century by the Hapsburgs, captured by Ottoman-backed corsairs and still looming over the sea approach to the city.

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The port beneath the fort was home to Barbarossa and a rabble of other Barbary pirates. But that’s not why the locals alight here. They’re making for the row of simple fish restaurants along Avenue Franklin Roosevelt. La Victoire isn’t the cheapest (a meal with locally caught sea bass, salads and wine costs £20), but it’s always good.

Stop two: if the Romans had had their way, we would know nothing about Carthage or its creators, the Phoenicians. The penalty for the Carthaginian general Hannibal daring to walk his war elephants across the Alps to threaten Rome was oblivion: Carthage was demolished and the land it stood on ploughed over with salt.

But the location is so spectacular that, within a couple of generations, the Romans constructed a magnificent new city. French colonisers later built seaside villas over some of the ruins, now part of a particularly beautiful palm-shaded suburb.

Get out at Carthage Dermech station and walk up Byrsa Hill to the ruins and museum, an eloquent testament to past gore and glory. The view to the sea and the ancient port is beautiful, though perhaps best appreciated over lunch or a drink at the nearby Villa Didon hotel. The Antonine Baths, down on the waterfront, were the largest outside Rome until the Vandals demolished them. You can swim near here in the summer, or rejoin the TGM at Carthage Hannibal.

Stop three: Sidi Bou Saïd suffers for being one of the most beautiful villages on the Mediterranean – but, in spite of the coach tours, it remains a great place to stroll around, particularly in the evening when the crowds are local. Perched on cliffs, it was popular with 19th-century European artists and writers, and retains both its artistic reputation and its raffish air.

The attraction is immediately obvious. It’s an irresistible confection of white houses, light-blue doors hiding jasmine-scented gardens and, beyond, the brilliant sea. Among the many foreigners seduced by the place was a French banker, Baron Rodolphe d’Erlanger, a passionate painter (the Tate has one of his works) and Arab music enthusiast.

His palace, Dar Nejma Ezzahra (Star of Venus), now houses his collections. Sidi Bou Saïd’s best restaurant, Au Bon Vieux Temps, occupies an old house with a sea-view terrace, filled with locals later in the evening. Or head to Café Sidi Chabaane, perched on the cliff edge, with vertiginous views.

The finish: La Marsa is where Tunis’s 19th-century rulers preferred to spend their summers, and where more and more Tunisians choose to live year-round. There’s a sweeping beach and an air of affluence around here. Café Saf Saf, an old-style cafe in the shade of the mosque, has long been a favoured place to while away the moments with a mint tea – or head to one of the cool bars along the corniche before taking the TGM back to town.

Travel details: the TGM (from 55p) leaves Tunis every 15-20 minutes; the trip to La Marsa takes just over half an hour. For more information, visit www.snt.com.tn .

Getting there: fly nonstop from Gatwick, with British Airways (0870 850 9850, www.ba.com), or Heathrow, with Tunisair (020 7734 7644, www.tunisair.com ). Fares start at about £150.

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