The original stone fortifications of Mont-Saint-Michel were erected in the 13th century to protect the Mont and its abbey against invaders. They were reinforced later on, particularly at the beginning of the Hundred Years’ War. The ramparts surround the south and east sides of the rock, with a few defensive structures spread out over the rest of the island. The fortified enclosure is discontinuous: it only exists on the accessible points at low tide and stops where the natural defence is sufficient. Whilst it remains a place of pilgrimage during periods of wars, the Mont-Saint-Michel also serves the purposes of a military stronghold.