Although officially neither a park nor garden, this pioneering green passage couldn't be missed off our list. Built along a disused railway line, the 24km-long corridor slices right through the city, connecting many of Singapore's biggest green spaces while allowing wildlife movement between its major parks. Much of the area has been rewilded with native plants, and there are no lights along the corridor in order to encourage animals to pass through at night. Our advice? Hire a bike and cycle along its network of tracks and underpasses to experience a new dimension of this pea-green garden city.