KARST AWAY

With hundreds of limestone islands and outcrops rising like giant chess pieces from its turquoise waters, Ha Long Bay in northeastern Vietnam is among the most photogenic seascapes on earth. The conventional way to see this utterly beguiling World Heritage site is on one of the multiday cruises that weave through its karststudded archipelago. There are more than 500 registered vessels to choose from, ranging from backpacker-friendly rust buckets to small ships replete with butlers and day spas.

But there’s a more immersive (and less expensive) way to experience the area at Cat Ba Island, a UNESCO Biosphere Reserve that sits in Lan Ha Bay, a relatively unknown body of water just to the west of Ha Long. Cat Ba is the largest of Lan Ha’s 367 islands,