Vallée de Mai grows the heaviest seed in the plant kingdom — a two-lobed coco de mer nut that can weigh 25 kilograms. The palm that carries it grows wild nowhere but Praslin and neighbouring Curieuse, and roughly 8,000 mature trees are left. Everything about it is slow and outsized: a tree may stand for decades before it first flowers, its fan leaves stretch up to ten metres, and male palms hang catkins two metres long. The shapes were suggestive enough that when General Charles Gordon came ashore in 1881 he pronounced this valley the Garden of Eden and the coco de mer its forbidden fruit. All six palm species endemic to Seychelles grow side by side here and in no other forest — 19.5 hectares of granite valley left uncut until the 1930s, protected in 1966 and inscribed by UNESCO in 1983.
Inside, daylight comes down in shafts through thirty metres of overlapping fans, and the loudest sound is dry fronds knocking in the wind — until a harsh whistle cuts across it. That is the Seychelles black parrot, the national bird, which lives on this island alone and nests almost only in the hollow trunks of dead coco de mer palms. Sandy paths loop past stilt palms braced on bare granite, a stream holding the country's only endemic freshwater fish and its only freshwater crab, and geckos found in no other canopy. The valley is guarded now rather than simply visited: the coco de mer was uplisted to Endangered after years of nut poaching and fire, wardens patrol the slopes, and no nut leaves the island without a numbered government tag.