If you're willing to go off the main path, bash through some super tall ferns and wild grass, and get slightly scratched by thorny plants and stems to find the secret Keppel Hill Reservoir, you will be greatly rewarded. There's nothing like a challenging hike or the beautiful and elusive views at the end. Formerly used as a private reservoir in 1905 and then a swimming hole from the 1940s, this body of water was totally left out on official maps of Singapore from 1954 onwards.

First things first: the solitary cow on Coney Island is no longer there but there are still plenty of things to see on this rustic island in the North-East of Singapore, including hidden beaches and the unoccupied Haw Par Beach Villa. Built in 1937 by the Aw brothers (the duo behind Tiger Balm and Haw Par Villa), the single-story villa comes complete with an open verandah. It's said that the brothers owned it until the 1950s before the government acquired it in the 1970s.

This rail corridor was formerly a railway line used for commuting and transporting goods from Singapore to the rest of the Malay Peninsula. Today, the 24-kilometre route has been converted into neighbourhoods and parks. Discover the untouched Clementi Forest near the former Bukit Timah Railway Station – but be prepared to go off-trail. Hike through muddy paths and trails to see a sprawling valley, or trudge through thick vegetation to uncover old rail tracks.

The Alexandra Woodland is a small patch of wilderness which lies next to the Rail Corridor, opposite Alexandra Hospital and next to the Ayer Rajah Expressway. Start the trek from Portsdown Avenue and stick close to the main path to get there. The main attraction of this trail is the magnificent 'Lost Ark' structure made from giant fallen trees next to a natural pond. As it's an off-trail location, do hike at your own risk – always wear proper attire and walking shoes.

Continue along the Pasir Ris park connector towards Tampines and you’ll come across sprawling greenery formed by open grasslands, freshwater wetlands and a secondary rainforest. You’d never guess that this green space exists, wrapping around one of the most populous neighbourhoods in Singapore. Wade through the greens as you take on the walking trail within the sanctuary to uncover its rich biodiversity, featuring many species of birds, butterflies, dragonflies and spiders.

This hidden WWII bunker at the foot of Mount Faber is located behind the Seah Im carpark. Built into a slope, the entrance leads to a tunnel that’s connected to the elongated bunker. As it is dark in the bunker, bring torchlights to guide your exploration. Those who have a fear of geckos, however, be wary, as long disuse has turned the bunker into a nesting ground for the reptile. Tree roots have also grown through the ventilation holes on the walls.

Dover Forest is a modest 33-hectare piece of land easily accessible from either Buona Vista or Dover MRT. It was part of a rubber plantation that was abandoned after WWII, and has been sitting untouched since the 1980s. Thick undergrowth and random tree stumps have to be dodged around, and there are veiny roots underfoot that threaten to trip you at any moment. But the trek is well worth it – at some point, you will emerge into open fields of green foliage and may even spot some wildlife.