Cars drive along a stretch of highway on the perimeters of the central catchment area in Singapore March 2, 2016. A plan to build a subway tunnel under Singapore's largest patch of primary rainforest has drawn sharp protests from environmental groups and activists who say it could irreversibly damage the habitats of hundreds of plant and animal species. REUTERS/Edgar Su SEARCH "RAINFOREST CITY" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES