Horton Plains is a grassland plateau above 2,100 metres in the central highlands of Sri Lanka, cold, misty and treeless, that breaks off without warning in a cliff 1,200 metres high called World's End, from which at dawn on a clear day the Indian Ocean glints eighty kilometres to the south. The plateau is the highest in the country, a rolling plain of tussock grass and pockets of cloud forest where frost stiffens the grass on winter mornings, and it is walked on a loop of about nine kilometres from the gate to the cliff edge and back. The trick is the hour: the clear window is short, and once the day warms, cloud climbs the cliff and closes the view for good, usually by nine, so the walk starts at the gate's opening in the dark and reaches World's End with the sun; then the plateau ends in a sheer drop, the ground falls away beneath your feet, and the tea country lies far below with the coast beyond it. In the cool early hours sambar deer, the largest in Sri Lanka, step out of the forest to feed on the open grass, unbothered by walkers.
On the return leg a short side path drops through mossy cloud forest to Baker's Falls, where a broad curtain of water crashes over dark rock into a cold pool, named for Samuel Baker, later famous as a Nile explorer, who tried to plant an English farming colony in these hills in the 1840s. The plateau holds one of the rarest primates on Earth, the Horton Plains slender loris, a nocturnal animal photographed for the first time here in 2010 after years in which scientists feared it extinct, and the forest patches shelter leopards that are almost never seen. The dry window from January to March gives the clearest dawns, and the rest of the year the cliff is in cloud more often than not. Horton Plains is a cold plain on a tropical island, and the edge of it is the edge of the world.