Silent Valley National Park

Silent Valley National Park in the Nilgiri Hills of northern Kerala protects one of the largest unlogged tracts of tropical wet evergreen forest in peninsular India, part of the broader Nilgiri Biosphere Reserve. The park is named for an absence of cicadas — attributed historically to its unusual biodiversity — and is home to lion-tailed macaques, Nilgiri langurs, and an exceptional diversity of endemic flora. Access is strictly controlled and requires forest-department permits.