Tristan da Cunha, circa 1870. This small group of islands in the southern Atlantic Ocean is the most remote archipelago in the world. Photographed during the voyage of HMS Challenger (1872-1876). This scientific expedition, organised by the Royal Society, spent four years surveying the world's oceans. The ship was equipped with a dark room, enabling development of the photographs taken of the lands and peoples encountered. It is thought that this expedition was the first to include routine photography as well as an official artist.