The National Geospatial-Intelligence Agency lists 41 lighthouses in the waterway. Some of them are more than a century old, and some are declared Monumento Nacional ("national monument"). Among the most notable lighthouses are: County of Peebles hulk, the world's first four-masted, iron-hulled "full-rig ship",[57] used now as a breakwater for the harbour at Punta Arenas; the San Isidro lighthouse, restored in 2004 and is now a museum and lodge;[58] and the Evangelistas Lighthouse, located at the western mouth of the strait and built by George Slight, who wrote on his arrival in 1934: