Langkawi is ninety-nine rainforest islands off the northwest corner of Malaysia, and the thing most people come for hangs 660 metres up: a curved footbridge across the top of a mountain. The mountain is Gunung Mat Cincang, and the sandstone under the deck was laid down more than 550 million years ago, the oldest exposed rock in Southeast Asia. A cable car lifts you to it from the coast, and the Sky Bridge picks up beyond the top station: 125 metres of steel slung from a single mast, out over the canopy with almost nothing beneath it. Because the deck curves, the view swings as you walk, forest, then the strait, then forest again, never the same frame twice. The span gives a little underfoot with every step, and glass panels in the floor put the treetops directly below your shoes. The walk out and the walk back look nothing alike. There was no road to the summit, so the bridge was built in sections on the ground and flown up by helicopter.
Down at sea level the island is sand and boats. Pantai Cenang is the busy white strip on the west coast; Tanjung Rhu in the north is the quiet one, lined with casuarinas, where late afternoon turns the Andaman Sea copper as the fishing boats head out. The east is met from the water. The rock there is limestone, tens of millions of years younger, standing in cliffs that come straight up out of the sea. Tidal channels wind through the Kilim mangroves between them, brahminy kites riding the warm air overhead and macaques picking along the roots at low tide. Further out, the boats reach Dayang Bunting, where a freshwater lake sits in a bowl of marble just inland of the sea, held off by a narrow ridge of limestone. The two rocks were pushed together long after they formed. The mountain you crossed in the morning is half a billion years older than the cliffs the boat threads in the afternoon, and both are green to the waterline.