Once attached to the mainland, this mammoth rock wall is 438m/1,437ft long and 88m/289ft high. At one time the limestone block may have had up to four archways. One of them crumbled in 1845, leaving a detached slab called the Obelisk. Today only a 30m/94ft arch remains. The sculptured limestone rock is connected to Mont Joli by a sandbar, accessible at low tide.