Avignon's compact medieval centre lends itself to exploring on foot. For most visitors, the obvious place to start is in Place de l'Horloge, the city's main square and atmospheric, charming heart. Overlooked by the monumental clock that gives the square its name, plus the impressive, 19th-century façades of the town hall and opera house, this is an ideal spot for a leisurely lunch at a pavement bistro beneath the plane trees. From there, stroll northwards through winding streets to the Palais des Papes and Avignon Cathedral. The latter is well worth a visit for its stunning, 12th-century basilica filled with paintings, its papal tombs and the bell tower topped with a gilded statue of the Virgin Mary. Beyond the cathedral is the Jardin des Doms, perched atop the Rocher des Doms and offering mesmerising views across the city, the river and the surrounding countryside. It is one of the most peaceful spots in Avignon, with paths wandering among English-style landscaped flower beds and water features. From the gardens, it's a short step to the Rhône, spanned by a legendary crossing – the medieval bridge forever immortalised in the famous French song Sur le Pont d'Avignon – or as it is more properly known, the Pont Saint Bénezet. This was once the only place to cross the river between Lyon and the Mediterranean Sea, and although it was repeatedly damaged by floods over the centuries, it remains one of the best-known sights in Avignon, beloved for its historic chapel and graceful Romanesque arches. For an antidote to the city's medieval culture, turn south to the Collection Lambert, a magnificent display of contemporary art from big names including Cy Twombly and Jean-Michel Basquiat, housed in two elegant mansions.