Halong Bay: Just a short few hours from Hanoi, the bay at Halong, with its craggy limestone towers dotting the wide-open bay all the way to the horizon, has long inspired Vietnamese poets and philosophers. A ride on the bay these days is a rather busy, crowded affair, but some luxury tours and a few eco-tour operators can take you to the back of beyond, exploring little-known caves by kayak.
Phong Nha -- Ke Bang National Park: These massive caves (more or less an off-the-track site popular with backpackers) are about halfway between Hue and Vinh. You have to arrange your own transport or go with a tour.
Hoi An: Tourism has exploded on the ancient streets of Hoi An. A hub of international craft and commerce since the 14th century, this is where Vietnamese, Chinese, and even Japanese tradesmen made and sold their designer wares. Many shops are still-operational wood, stone, and ceramic workshops, but now among them are fine-dining outlets, funky little hotels (as well as new resorts on the outlying beach area of Cua Dai), and lots of bespoke tailors. Shoppers swoon.
My Son Sanctuary: The Cham people, an Indonesian group who arrived by ship from the Malay Peninsula, held sway over most of central Vietnam and built arching hilltop towers. My Son is the finest example.
Hue Monuments: The Nguyen Kings -- the last and perhaps the most glorious (or grandiose) of Vietnam's dynastic rulers -- built grand monuments to themselves in and around the massive Hue Citadel. Hue's sights, particularly the elaborate kings' tombs, make for a very interesting visit.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.