The best way to get a handle on Singapore’s geography is to take a cruise on the Singapore River, upstream from the bay to Robertson Quay.
You can choose from a traditional bumboat or a modern glass-roofed cruiser, with an entertaining and informative onboard commentary.
You’ll see more by day, but by night the experience is more romantic as the boats are atmospherically lit with red Chinese lanterns. You could also combine sightseeing and a meal with a dinner cruise along the river.