Topped by Singapore's tallest hill, Bukit Timah Nature Reserve (nparks.gov.sg) is a swath of primary rainforest embellished with hiking trails and bike paths. Once teeming with tigers, this is the only reserve that has been protected under the management of the Singapore Botanic Gardens since the 1930s (the other reserves were all worked for timber). The last tiger was shot in the 1920s, but you'll still find plenty of long-tailed macaques and dozens of bird species.
The 163-hectare sprawl is crisscrossed by five well-established walking trails that range in length and difficulty (return trips take 35 minutes to two hours), plus a popular 6km mountain-bike trail. You can rent bikes, helmets and other gear from Unsprung (unsprung.com.sg; bike rental from S$50) along Hindhede Rd – book in advance if you can.
For those who prefer to explore on foot, the quickest, most popular hike is the one leading to the summit of Bukit Timah (163m), Singapore's highest peak.
To get to the reserve, take the MRT to Beauty World MRT Station (Exit A) and walk towards Hindhede Dr, where you'll find the reserve's official entrance. It has a visitors center with restrooms, water fountains and an exhibition on the forest's flora and fauna. Take plenty of water, smother yourself in mosquito repellent – and don't feed the monkeys, no matter how cute they are!