Towering limestone pillars and tiny islets topped by forest rise from the emerald waters of the Gulf of Tonkin. Designated a World Heritage Site in 1994, Halong Bay's scatter of islands, dotted with wind- and wave-eroded grottoes, is a vision of ethereal beauty and, unsurprisingly, northern Vietnam's number one-tourism hub. Sprawling Halong City (also known as Bai Chay) is the bay's main gateway, but its high-rises are a disappointing doorstep to this site. Most visitors opt for cruise tours that include sleeping on board within the bay, while a growing number are deciding to eschew the main bay completely, heading straight for Cat Ba Island from where trips to less-visited but equally alluring Lan Ha Bay are easily set up. All visitors must purchase entry tickets for the national park (40,000d) and there are also separate admission tickets for attractions in the bay, such as caves and fishing villages (30,000d to 50,000d).