Ha Long Bay

Nearly 2,000 limestone islands and pillars rise from the emerald water of the Gulf of Tonkin, making one of the most spectacular seascapes in the world and a UNESCO World Heritage Site. The best way to see it is on an overnight cruise: you sail among the karsts, kayak through caves and lagoons, visit caves such as Sung Sot, and watch the sunset and sunrise from the deck.

Boats range from budget junks to luxury ships, including the Emeraude, a replica of an early 20th-century French steamer. Choose a reputable company, as standards vary widely. For fewer boats, choose a cruise to Bai Tu Long Bay or to Lan Ha Bay, which can also be reached from Cat Ba Island.

Ha Long City is about 2.5 to 3 hours from Hanoi by expressway, and most cruises include the transfer. The weather is best from about March to May and September to November.