Singapore’s steamy Bukit Timah Nature Reserve is a 163-hectare tract of primary rainforest clinging to Singapore’s highest peak, Bukit Timah (163m). The reserve supposedly holds more tree species than the entire North American continent, and its unbroken forest canopy shelters what remains of Singapore’s native wildlife, including long-tailed macaques, pythons and dozens of bird species. The visitor centre (8am to 5.30pm) showcases the area's flora and fauna, including two Sumatran tigers who once roamed Singapore.
Also, keep in mind that the steep paths are sweaty work, so take plenty of water, smother yourself in mosquito repellent, and don’t feed the monkeys no matter how politely they ask.