The 90-kilometre stretch of the Rhône between Avignon and Arles was, for centuries, the principal commercial artery of Provence. Flat-bottomed barges laden with wheat, salt, and wine moved south toward the Mediterranean under oar and sail, while returning vessels hauled Marseille's imports north toward Lyon. The papal city commanded the river's upper reach; the Roman settlement of Arles controlled the delta. Between them, the current carved a corridor through vineyards, quarries, and fortified mills that supplied both cities with grain and stone. Today the Rhône carries leisure traffic where cargo once moved. A boat trip Avignon to Arles retraces that medieval trade route, passing beneath the broken arches of Pont Saint-Bénézet and the limestone cliffs of Villeneuve-lès-Avignon before the river widens into the flat marshland of the Camargue. The journey takes four to five hours downstream, depending on the water level and the number of locks. Passengers disembark at Arles' Quai de la Roquette, a short walk from the Roman amphitheatre and the hospital where Vincent van Gogh was confined in 1889. The return leg, against the current, adds another hour. The Rhône's navigable section south of Avignon was engineered in the 19th century to bypass sandbars and seasonal floods. Lock gates at Vallabrègues and Beaucaire regulate the flow, allowing vessels to maintain a steady passage year-round. The riverbanks remain largely undeveloped — reeds, poplars, and occasional farmhouses replace the industrial sprawl that marks other European waterways. Migratory birds use the corridor as a flyway between the Alps and the Mediterranean; herons and egrets are common sightings from the deck. Arles itself holds Roman ruins second only to Rome in concentration. The amphitheatre seated 20,000 spectators; the theatre, still in use, was built under Augustus. The city's medieval core, compressed within ancient walls, preserves narrow streets and stone façades that van Gogh painted during his 15-month residence. His Yellow House no longer stands, but the café terrace and the Rhône's starry nights remain identifiable. A boat trip Avignon to Arles tickets include time ashore to walk the Roman circuit or visit the Fondation Vincent van Gogh, which opened in 2014 and rotates exhibitions pairing his work with contemporary artists. The cruise back to Avignon departs late afternoon, timed to catch the western light on the papal palace's limestone walls.