Marina Barrage

It was built to turn the bay into a freshwater reservoir and to hold back the tide, and the part visitors actually come for is the grassed roof on top of it — an open slope that catches the sea breeze and faces straight across the water to the city skyline. The grounds and rooftop are open around the clock and cost nothing to enter; people come up to fly kites, picnic and sit out the evening. Inside is the Sustainable Singapore Gallery, also free, running interactive displays on the country's water and environment story; it opens 9am to 6pm daily except Tuesdays, and closes over the lunch hour from noon to 1pm.

It is about a ten-minute walk south of Gardens by the Bay, so the two pair easily into one afternoon. The quickest way in is the sheltered underpass from Gardens by the Bay MRT (TE22) Exit 1, roughly a five-minute walk, rather than Bus 400, which many older guides still tell you to catch from Marina Bay station.

The roof is almost entirely unshaded, so at midday it is hot and the kites hang limp. Come from late afternoon instead, when the sea breeze picks up enough to actually fly a kite and you can watch the skyline light up — and on nights the Marina Bay Sands Spectra show runs, the roof gives you a free, uncrowded view of it across the water rather than fighting the crowd on the Sands boardwalk.