Sinharaja, the name meaning “Lion King”, is Sri Lanka’s last viable area of primary tropical rainforest and arguably the island’s most important natural heritage site. A UNESCO World Heritage Site and biodiversity hotspot of global significance, Sinharaja shelters an astonishing catalogue of life found nowhere else on earth: 26 of Sri Lanka’s 33 endemic bird species have been recorded here, along with 50% of endemic mammals, communities of endemic amphibians, and an understory of ancient trees draped in mosses, lianas, and orchids so dense that the forest floor remains in perpetual green twilight. A guided trek through the forest with an expert local naturalist is an immersive, deeply engaging experience. The guiding quality at Sinharaja is among the finest in Asia, and the endemic birds, including the iridescent blue magpie, the scarlet-faced red-faced malkoha, and the rare green-billed coucal, move through the canopy in noisy mixed-species feeding flocks that can surround you on all sides simultaneously. For naturalists and photographers, this is unmissable.