Formerly attached to the mainland, this gigantic rocky islet is 438m/1,437ft long and 88m/289ft high. The limestone block may once have had up to four archways. One of these crumbled in 1845, leaving a detached slab called the Obelisk and today only a 30m/94ft arch remains. This is connected to Mont Joli by a sandbar, accessible at low tide.