Mont St-Michel's one main street, the Grande Rue, leads up the slope – past souvenir shops, eateries and a forest of elbows – to the star attraction of a visit here, a stunning ensemble crowning the top: the abbey. History Bishop Aubert of Avranches is said to have built a devotional chapel on the summit of the island in 708, following his vision of the Archangel Michael, whose gilded figure, perched on the vanquished dragon, crowns the tip of the abbey’s spire. In 966, Richard I, Duke of Normandy, gave Mont St-Michel to the Benedictines, who turned it into a center of learning and, in the 11th century, into something of an ecclesiastical fortress, with a military garrison at the disposal of both abbot and king. In the 15th century, during the Hundred Years War, the English blockaded and besieged Mont St-Michel three times. The fortified abbey withstood these assaults and was the only place in western and northern France not to fall into English hands. After the Revolution, Mont St-Michel was turned into a prison. In 1966 the abbey was symbolically returned to the Benedictines as part of the celebrations marking its millennium. Mont St-Michel and the bay became a Unesco World Heritage Site in 1979. Guided tours Most areas of the abbey can be visited without a guide, but check if the 1¼-hour tour is running; English tours (usually) begin at 11am and 3pm from October to March, with three or four daily tours in spring and summer. You can also take a one-hour audio guide tour, available in 10 languages. Tickets and other practicalities Tickets and audio guides should be booked online in advance. Audio guides are available for a small fee, and must be requested as part of your advance booking. Benedictine monks hold services in the abbey, which are free for worshippers.